【问题标题】:htmlentities() vs. htmlspecialchars()htmlentities() 与 htmlspecialchars()
【发布时间】:2026-02-09 04:05:02
【问题描述】:

htmlspecialchars()htmlentities() 有什么区别。我应该什么时候使用其中一种?

【问题讨论】:

    标签: php


    【解决方案1】:

    来自htmlentities 的 PHP 文档:

    这个函数在所有方面都与htmlspecialchars() 相同,除了htmlentities(),所有具有HTML 字符实体等价物的字符都被翻译成这些实体。

    来自htmlspecialchars 的 PHP 文档:

    某些字符在 HTML 中具有特殊意义,如果要保留其含义,则应由 HTML 实体表示。该函数返回一个字符串,其中包含一些转换;所做的翻译是那些对日常网络编程最有用的。如果您需要翻译所有 HTML 字符实体,请改用 htmlentities()

    区别在于编码的内容。选择是所有字符(实体)或“特殊”字符,例如与号、双引号和单引号、小于和大于(特殊字符)。

    我更喜欢尽可能使用htmlspecialchars

    例如:

        echo htmlentities('<Il était une fois un être>.');
        // Output: &lt;Il &eacute;tait une fois un &ecirc;tre&gt;.
        //                ^^^^^^^^                 ^^^^^^^
    
        echo htmlspecialchars('<Il était une fois un être>.');
        // Output: &lt;Il était une fois un être&gt;.
        //                ^                 ^
    

    【讨论】:

    • 感谢您的回答,但除了明显的差异之外,您是否介意尽可能详细说明您更喜欢htmlspecialchars() 的内容?哪些情况下使用htmlentities() 会导致问题而htmlspecialchars() 不会?
    • 由于使用 htmlentities 而不是 htmlspecialchars 而遇到了问题!如果您的网站是 UTF8 编码的,像 ¡™£¢∞§¶ 这样的特殊符号会变成带有问号的黑色小菱形,因为 htmlentities 不知道如何处理它们,但 htmlspecialchars 知道。
    • @Darius 你所说的没有任何意义。 htmlentitieshtmlspecialchars 都可以处理 UTF-8,只要您为第三个参数指定 "UTF-8"
    • 从 PHP 5.4 开始,UTF-8 是默认的编码选项(第三个参数)。
    • @Darius:我们遇到了类似的情况。像我们一样,您可能使用的是早于 5.4.0 的 PHP。因此,从 Jonathan 的评论推断,我们需要像这样显式指定 UTF-8:htmlentities($str, ENT_QUOTES, 'UTF-8');
    【解决方案2】:

    这是用htmlentities 编码的。

    implode( "\t", array_values( get_html_translation_table( HTML_ENTITIES ) ) ):

    " &
    ¡ ¢ £ ¤ ¥ ¦ § ¨ © ª « ¬ ® ¯ ° ± ² ³ ´ µ ¶ · ¸ ¹ º » ¼ ½ ¾ ¿ À Á Â Ã Ä Å Æ Ç È É Ê Ë Ì Í Î Ï ¡ þ ÿ Œ – Š š Ÿ ƒ ˆ ∼ Α Β Γ Δ Ε ζ Η Θ Ι Κ Λ Μ Ν Ξ Ο Π Ρ Σ Τ Υ Φ Χ Ψ Ω α β γ δ ε ζ η θ ι κ λ μ ν ξ ο π ρ ς σ τ υ φ χ ψ ω ϑ ϒ ϖ       ‌ ‍ ‏ – — ‘ ’ ‚ “ ” „ † ‡ • … ‰ ′ ″ ‹ › ‾ ⁄ € ℑ ℘ ℜ ™ ℵ ← ↑ → ↓ ↔ ↵ ⇐ ⇑ ⇒ ⇓ ⇔ ∀ ∂ ∃ ∅ ∇ ∈ ∉ ∋ ∏ ∑ − ∗ √ ∝ ∞ ∠ ∧ ∨ ∩ ∪ ∫ ∴ ∼ ≅ ≈ ≠ ≡ ≤ ≥ ⊂ ⊃ ⊄ ⊉ ⊇ ⊕ ⊗ ⊥ ⋅ ⊕ ⊗ ⊥ ⋅ ∪ ⟩ ◊ ♠ ♣ ♥ ♦

    这是用htmlspecialchars 编码的。

    implode( "\t", array_values( get_html_translation_table( HTML_SPECIALCHARS ) ) ):

    " &

    【讨论】:

    • 当心!乍一看,htmlentities 看起来相当完整。但它缺少一堆非常基本和常见的字符(尤其是如果您的客户喜欢 MS)。智能引号(例如 ' 或 ’)、破折号(例如 — 或 &mdash)、商标符号(™ 或 ™)以及许多其他字符都会导致它返回 null。
    • @Jonathan 这些都在列表中。如果你得到一个空的结果,那么你可能指定的编码不正确。
    • 或者你没有指定编码,并且依赖于默认值,它在 PHP 5.4 中发生了变化,然后(可能)在 PHP 5.6 中再次发生变化,具体取决于你的配置。直到 2012 年,文档甚至都不建议您指定参数。所以,如果你没有指定 optional 第三个参数,并且升级了 PHP,htmlentities 首先使用 ISO-8859-1,然后它使用 UTF-8,然后它使用你 php.ini 中的任何内容,而不是在任何问题上抛出错误,但悄悄地什么也不返回。显然,这永远不可能在某些时候导致数据丢失!
    • 这些列表中未显示的是 (1) 这两个函数都对空格进行编码(如 %20),以及 (2) 您可以设置一个标志 (ENT_QUOTES) 以便它们也对单引号进行编码.
    【解决方案3】:

    htmlspecialchars() 和 htmlentities() 之间的区别非常小。让我们看一些例子:

    htmlspecialchars

    htmlspecialchars(string $string) 接受多个参数,其中第一个参数是字符串,所有其他参数(某些标志、某些编码等)都是可选的。 htmlspecialchars 将字符串中的特殊字符转换为 HTML 实体。例如,如果您的字符串中有 ,则 htmlspecialchars 会将其转换为 < b>。而像 µ † 等字符在 HTML 中没有特殊意义。因此,它们不会被 htmlspecialchars 函数转换为 HTML 实体,如下例所示。

    echo htmlspecialchars('An example <br>'); // This will print - An example &lt; br &gt;
    echo htmlspecialchars('µ †');             // This will print -  µ †
    

    html实体

    htmlentities (string $string)htmlspecialchars 非常相似,并接受多个参数,其中第一个参数是字符串,所有其他参数都是可选的(某些标志,某些编码等)。与 htmlspecialchars 不同,htmlentities 不仅将字符串中的特殊字符转换为 HTML 实体,还将所有适用的字符转换为 HTML 实体。

    echo htmlentities('An example <br>'); // This will print - An example &lt; br &gt;
    echo htmlentities('µ †');             // This will print -  &micro; &dagger; 
    

    【讨论】:

      【解决方案4】:
      **HTML Character Entity Reference Chart at W3.org**
      

      https://dev.w3.org/html5/html-author/charref

      &Tab;
      &NewLine;
      !
      &excl;
      "
      &quot; &QUOT;
      #
      &num;
      $
      &dollar;
      %
      &percnt;
      &
      &amp; &AMP;
      '
      &apos;
      (
      &lpar;
      )
      &rpar;
      *
      &ast; &midast;
      +
      &plus;
      ,
      &comma;
      .
      &period;
      /
      &sol;
      :
      &colon;
      ;
      &semi;
      <
      &lt; &LT;
      =
      &equals;
      >
      &gt; &GT;
      ?
      &quest;
      @
      &commat;
      [
      &lsqb; &lbrack;
      \
      &bsol;
      ]
      &rsqb; &rbrack;
      ^
      &Hat;
      _
      &lowbar;
      `
      &grave; &DiacriticalGrave;
      {
      &lcub; &lbrace;
      |
      &verbar; &vert; &VerticalLine;
      }
      &rcub; &rbrace;
      
      &nbsp; &NonBreakingSpace;
      ¡
      &iexcl;
      ¢
      &cent;
      £
      &pound;
      ¤
      &curren;
      ¥
      &yen;
      ¦
      &brvbar;
      §
      &sect;
      ¨
      &Dot; &die; &DoubleDot; &uml;
      ©
      &copy; &COPY;
      ª
      &ordf;
      «
      &laquo;
      ¬
      &not;
      &shy;
      ®
      &reg; &circledR; &REG;
      ¯
      &macr; &OverBar; &strns;
      °
      &deg;
      ±
      &plusmn; &pm; &PlusMinus;
      ²
      &sup2;
      ³
      &sup3;
      ´
      &acute; &DiacriticalAcute;
      µ
      &micro;
      ¶
      &para;
      ·
      &middot; &centerdot; &CenterDot;
      ¸
      &cedil; &Cedilla;
      ¹
      &sup1;
      º
      &ordm;
      »
      &raquo;
      ¼
      &frac14;
      ½
      &frac12; &half;
      ¾
      &frac34;
      ¿
      &iquest;
      À
      &Agrave;
      Á
      &Aacute;
      Â
      &Acirc;
      Ã
      &Atilde;
      Ä
      &Auml;
      Å
      &Aring;
      Æ
      &AElig;
      Ç
      &Ccedil;
      È
      &Egrave;
      É
      &Eacute;
      Ê
      &Ecirc;
      Ë
      &Euml;
      Ì
      &Igrave;
      Í
      &Iacute;
      Î
      &Icirc;
      Ï
      &Iuml;
      Ð
      &ETH;
      Ñ
      &Ntilde;
      Ò
      &Ograve;
      Ó
      &Oacute;
      Ô
      &Ocirc;
      Õ
      &Otilde;
      Ö
      &Ouml;
      ×
      &times;
      Ø
      &Oslash;
      Ù
      &Ugrave;
      Ú
      &Uacute;
      Û
      &Ucirc;
      Ü
      &Uuml;
      Ý
      &Yacute;
      Þ
      &THORN;
      ß
      &szlig;
      à
      &agrave;
      á
      &aacute;
      â
      &acirc;
      ã
      &atilde;
      ä
      &auml;
      å
      &aring;
      æ
      &aelig;
      ç
      &ccedil;
      è
      &egrave;
      é
      &eacute;
      ê
      &ecirc;
      ë
      &euml;
      ì
      &igrave;
      í
      &iacute;
      î
      &icirc;
      ï
      &iuml;
      ð
      &eth;
      ñ
      &ntilde;
      ò
      &ograve;
      ó
      &oacute;
      ô
      &ocirc;
      õ
      &otilde;
      ö
      &ouml;
      ÷
      &divide; &div;
      ø
      &oslash;
      ù
      &ugrave;
      ú
      &uacute;
      û
      &ucirc;
      ü
      &uuml;
      ý
      &yacute;
      þ
      &thorn;
      ÿ
      &yuml;
      Ā
      &Amacr;
      ā
      &amacr;
      Ă
      &Abreve;
      ă
      &abreve;
      Ą
      &Aogon;
      ą
      &aogon;
      Ć
      &Cacute;
      ć
      &cacute;
      Ĉ
      &Ccirc;
      ĉ
      &ccirc;
      Ċ
      &Cdot;
      ċ
      &cdot;
      Č
      &Ccaron;
      č
      &ccaron;
      Ď
      &Dcaron;
      ď
      &dcaron;
      Đ
      &Dstrok;
      đ
      &dstrok;
      Ē
      &Emacr;
      ē
      &emacr;
      Ė
      &Edot;
      ė
      &edot;
      Ę
      &Eogon;
      ę
      &eogon;
      Ě
      &Ecaron;
      ě
      &ecaron;
      Ĝ
      &Gcirc;
      ĝ
      &gcirc;
      Ğ
      &Gbreve;
      ğ
      &gbreve;
      Ġ
      &Gdot;
      ġ
      &gdot;
      Ģ
      &Gcedil;
      Ĥ
      &Hcirc;
      ĥ
      &hcirc;
      Ħ
      &Hstrok;
      ħ
      &hstrok;
      Ĩ
      &Itilde;
      ĩ
      &itilde;
      Ī
      &Imacr;
      ī
      &imacr;
      Į
      &Iogon;
      į
      &iogon;
      İ
      &Idot;
      ı
      &imath; &inodot;
      IJ
      &IJlig;
      ij
      &ijlig;
      Ĵ
      &Jcirc;
      ĵ
      &jcirc;
      Ķ
      &Kcedil;
      ķ
      &kcedil;
      ĸ
      &kgreen;
      Ĺ
      &Lacute;
      ĺ
      &lacute;
      Ļ
      &Lcedil;
      ļ
      &lcedil;
      Ľ
      &Lcaron;
      ľ
      &lcaron;
      Ŀ
      &Lmidot;
      ŀ
      &lmidot;
      Ł
      &Lstrok;
      ł
      &lstrok;
      Ń
      &Nacute;
      ń
      &nacute;
      Ņ
      &Ncedil;
      ņ
      &ncedil;
      Ň
      &Ncaron;
      ň
      &ncaron;
      ʼn
      &napos;
      Ŋ
      &ENG;
      ŋ
      &eng;
      Ō
      &Omacr;
      ō
      &omacr;
      Ő
      &Odblac;
      ő
      &odblac;
      Œ
      &OElig;
      œ
      &oelig;
      Ŕ
      &Racute;
      ŕ
      &racute;
      Ŗ
      &Rcedil;
      ŗ
      &rcedil;
      Ř
      &Rcaron;
      ř
      &rcaron;
      Ś
      &Sacute;
      ś
      &sacute;
      Ŝ
      &Scirc;
      ŝ
      &scirc;
      Ş
      &Scedil;
      ş
      &scedil;
      Š
      &Scaron;
      š
      &scaron;
      Ţ
      &Tcedil;
      ţ
      &tcedil;
      Ť
      &Tcaron;
      ť
      &tcaron;
      Ŧ
      &Tstrok;
      ŧ
      &tstrok;
      Ũ
      &Utilde;
      ũ
      &utilde;
      Ū
      &Umacr;
      ū
      &umacr;
      Ŭ
      &Ubreve;
      ŭ
      &ubreve;
      Ů
      &Uring;
      ů
      &uring;
      Ű
      &Udblac;
      ű
      &udblac;
      Ų
      &Uogon;
      ų
      &uogon;
      Ŵ
      &Wcirc;
      ŵ
      &wcirc;
      Ŷ
      &Ycirc;
      ŷ
      &ycirc;
      Ÿ
      &Yuml;
      Ź
      &Zacute;
      ź
      &zacute;
      Ż
      &Zdot;
      ż
      &zdot;
      Ž
      &Zcaron;
      ž
      &zcaron;
      ƒ
      &fnof;
      Ƶ
      &imped;
      ǵ
      &gacute;
      ȷ
      &jmath;
      ˆ
      &circ;
      ˇ
      &caron; &Hacek;
      ˘
      &breve; &Breve;
      ˙
      &dot; &DiacriticalDot;
      ˚
      &ring;
      ˛
      &ogon;
      ˜
      &tilde; &DiacriticalTilde;
      ˝
      &dblac; &DiacriticalDoubleAcute;
      ̑
      &DownBreve;
      ̲
      &UnderBar;
      Α
      &Alpha;
      Β
      &Beta;
      Γ
      &Gamma;
      Δ
      &Delta;
      Ε
      &Epsilon;
      Ζ
      &Zeta;
      Η
      &Eta;
      Θ
      &Theta;
      Ι
      &Iota;
      Κ
      &Kappa;
      Λ
      &Lambda;
      Μ
      &Mu;
      Ν
      &Nu;
      Ξ
      &Xi;
      Ο
      &Omicron;
      Π
      &Pi;
      Ρ
      &Rho;
      Σ
      &Sigma;
      Τ
      &Tau;
      Υ
      &Upsilon;
      Φ
      &Phi;
      Χ
      &Chi;
      Ψ
      &Psi;
      Ω
      &Omega;
      α
      &alpha;
      β
      &beta;
      γ
      &gamma;
      δ
      &delta;
      ε
      &epsiv; &varepsilon; &epsilon;
      ζ
      &zeta;
      η
      &eta;
      θ
      &theta;
      ι
      &iota;
      κ
      &kappa;
      λ
      &lambda;
      μ
      &mu;
      ν
      &nu;
      ξ
      &xi;
      ο
      &omicron;
      π
      &pi;
      ρ
      &rho;
      ς
      &sigmav; &varsigma; &sigmaf;
      σ
      &sigma;
      τ
      &tau;
      υ
      &upsi; &upsilon;
      φ
      &phi; &phiv; &varphi;
      χ
      &chi;
      ψ
      &psi;
      ω
      &omega;
      ϑ
      &thetav; &vartheta; &thetasym;
      ϒ
      &Upsi; &upsih;
      ϕ
      &straightphi;
      ϖ
      &piv; &varpi;
      Ϝ
      &Gammad;
      ϝ
      &gammad; &digamma;
      ϰ
      &kappav; &varkappa;
      ϱ
      &rhov; &varrho;
      ϵ
      &epsi; &straightepsilon;
      ϶
      &bepsi; &backepsilon;
      Ё
      &IOcy;
      Ђ
      &DJcy;
      Ѓ
      &GJcy;
      Є
      &Jukcy;
      Ѕ
      &DScy;
      І
      &Iukcy;
      Ї
      &YIcy;
      Ј
      &Jsercy;
      Љ
      &LJcy;
      Њ
      &NJcy;
      Ћ
      &TSHcy;
      Ќ
      &KJcy;
      Ў
      &Ubrcy;
      Џ
      &DZcy;
      А
      &Acy;
      Б
      &Bcy;
      В
      &Vcy;
      Г
      &Gcy;
      Д
      &Dcy;
      Е
      &IEcy;
      Ж
      &ZHcy;
      З
      &Zcy;
      И
      &Icy;
      Й
      &Jcy;
      К
      &Kcy;
      Л
      &Lcy;
      М
      &Mcy;
      Н
      &Ncy;
      О
      &Ocy;
      П
      &Pcy;
      Р
      &Rcy;
      С
      &Scy;
      Т
      &Tcy;
      У
      &Ucy;
      Ф
      &Fcy;
      Х
      &KHcy;
      Ц
      &TScy;
      Ч
      &CHcy;
      Ш
      &SHcy;
      Щ
      &SHCHcy;
      Ъ
      &HARDcy;
      Ы
      &Ycy;
      Ь
      &SOFTcy;
      Э
      &Ecy;
      Ю
      &YUcy;
      Я
      &YAcy;
      а
      &acy;
      б
      &bcy;
      в
      &vcy;
      г
      &gcy;
      д
      &dcy;
      е
      &iecy;
      ж
      &zhcy;
      з
      &zcy;
      и
      &icy;
      й
      &jcy;
      к
      &kcy;
      л
      &lcy;
      м
      &mcy;
      н
      &ncy;
      о
      &ocy;
      п
      &pcy;
      р
      &rcy;
      с
      &scy;
      т
      &tcy;
      у
      &ucy;
      ф
      &fcy;
      х
      &khcy;
      ц
      &tscy;
      ч
      &chcy;
      ш
      &shcy;
      щ
      &shchcy;
      ъ
      &hardcy;
      ы
      &ycy;
      ь
      &softcy;
      э
      &ecy;
      ю
      &yucy;
      я
      &yacy;
      ё
      &iocy;
      ђ
      &djcy;
      ѓ
      &gjcy;
      є
      &jukcy;
      ѕ
      &dscy;
      і
      &iukcy;
      ї
      &yicy;
      ј
      &jsercy;
      љ
      &ljcy;
      њ
      &njcy;
      ћ
      &tshcy;
      ќ
      &kjcy;
      ў
      &ubrcy;
      џ
      &dzcy;
       
      &ensp;
       
      &emsp;
       
      &emsp13;
       
      &emsp14;
       
      &numsp;
       
      &puncsp;
       
      &thinsp; &ThinSpace;
       
      &hairsp; &VeryThinSpace;
      ​
      &ZeroWidthSpace; &NegativeVeryThinSpace; &NegativeThinSpace; &NegativeMediumSpace; &NegativeThickSpace;
      ‌
      &zwnj;
      ‍
      &zwj;
      ‎
      &lrm;
      ‏
      &rlm;
      ‐
      &hyphen; &dash;
      –
      &ndash;
      —
      &mdash;
      ―
      &horbar;
      ‖
      &Verbar; &Vert;
      ‘
      &lsquo; &OpenCurlyQuote;
      ’
      &rsquo; &rsquor; &CloseCurlyQuote;
      ‚
      &lsquor; &sbquo;
      “
      &ldquo; &OpenCurlyDoubleQuote;
      ”
      &rdquo; &rdquor; &CloseCurlyDoubleQuote;
      „
      &ldquor; &bdquo;
      †
      &dagger;
      ‡
      &Dagger; &ddagger;
      •
      &bull; &bullet;
      ‥
      &nldr;
      …
      &hellip; &mldr;
      ‰
      &permil;
      ‱
      &pertenk;
      ′
      &prime;
      ″
      &Prime;
      ‴
      &tprime;
      ‵
      &bprime; &backprime;
      ‹
      &lsaquo;
      ›
      &rsaquo;
      ‾
      &oline;
      ⁁
      &caret;
      ⁃
      &hybull;
      ⁄
      &frasl;
      ⁏
      &bsemi;
      ⁗
      &qprime;
       
      &MediumSpace;
      ⁠
      &NoBreak;
      ⁡
      &ApplyFunction; &af;
      ⁢
      &InvisibleTimes; &it;
      ⁣
      &InvisibleComma; &ic;
      €
      &euro;
      ⃛
      &tdot; &TripleDot;
      ⃜
      &DotDot;
      ℂ
      &Copf; &complexes;
      ℅
      &incare;
      ℊ
      &gscr;
      ℋ
      &hamilt; &HilbertSpace; &Hscr;
      ℌ
      &Hfr; &Poincareplane;
      ℍ
      &quaternions; &Hopf;
      ℎ
      &planckh;
      ℏ
      &planck; &hbar; &plankv; &hslash;
      ℐ
      &Iscr; &imagline;
      ℑ
      &image; &Im; &imagpart; &Ifr;
      ℒ
      &Lscr; &lagran; &Laplacetrf;
      ℓ
      &ell;
      ℕ
      &Nopf; &naturals;
      №
      &numero;
      ℗
      &copysr;
      ℘
      &weierp; &wp;
      ℙ
      &Popf; &primes;
      ℚ
      &rationals; &Qopf;
      ℛ
      &Rscr; &realine;
      ℜ
      &real; &Re; &realpart; &Rfr;
      ℝ
      &reals; &Ropf;
      ℞
      &rx;
      ™
      &trade; &TRADE;
      ℤ
      &integers; &Zopf;
      Ω
      &ohm;
      ℧
      &mho;
      ℨ
      &Zfr; &zeetrf;
      ℩
      &iiota;
      Å
      &angst;
      ℬ
      &bernou; &Bernoullis; &Bscr;
      ℭ
      &Cfr; &Cayleys;
      ℯ
      &escr;
      ℰ
      &Escr; &expectation;
      ℱ
      &Fscr; &Fouriertrf;
      ℳ
      &phmmat; &Mellintrf; &Mscr;
      ℴ
      &order; &orderof; &oscr;
      ℵ
      &alefsym; &aleph;
      ℶ
      &beth;
      ℷ
      &gimel;
      ℸ
      &daleth;
      ⅅ
      &CapitalDifferentialD; &DD;
      ⅆ
      &DifferentialD; &dd;
      ⅇ
      &ExponentialE; &exponentiale; &ee;
      ⅈ
      &ImaginaryI; &ii;
      ⅓
      &frac13;
      ⅔
      &frac23;
      ⅕
      &frac15;
      ⅖
      &frac25;
      ⅗
      &frac35;
      ⅘
      &frac45;
      ⅙
      &frac16;
      ⅚
      &frac56;
      ⅛
      &frac18;
      ⅜
      &frac38;
      ⅝
      &frac58;
      ⅞
      &frac78;
      ←
      &larr; &leftarrow; &LeftArrow; &slarr; &ShortLeftArrow;
      ↑
      &uarr; &uparrow; &UpArrow; &ShortUpArrow;
      →
      &rarr; &rightarrow; &RightArrow; &srarr; &ShortRightArrow;
      ↓
      &darr; &downarrow; &DownArrow; &ShortDownArrow;
      ↔
      &harr; &leftrightarrow; &LeftRightArrow;
      ↕
      &varr; &updownarrow; &UpDownArrow;
      ↖
      &nwarr; &UpperLeftArrow; &nwarrow;
      ↗
      &nearr; &UpperRightArrow; &nearrow;
      ↘
      &searr; &searrow; &LowerRightArrow;
      ↙
      &swarr; &swarrow; &LowerLeftArrow;
      ↚
      &nlarr; &nleftarrow;
      ↛
      &nrarr; &nrightarrow;
      ↝
      &rarrw; &rightsquigarrow;
      ↞
      &Larr; &twoheadleftarrow;
      ↟
      &Uarr;
      ↠
      &Rarr; &twoheadrightarrow;
      ↡
      &Darr;
      ↢
      &larrtl; &leftarrowtail;
      ↣
      &rarrtl; &rightarrowtail;
      ↤
      &LeftTeeArrow; &mapstoleft;
      ↥
      &UpTeeArrow; &mapstoup;
      ↦
      &map; &RightTeeArrow; &mapsto;
      ↧
      &DownTeeArrow; &mapstodown;
      ↩
      &larrhk; &hookleftarrow;
      ↪
      &rarrhk; &hookrightarrow;
      ↫
      &larrlp; &looparrowleft;
      ↬
      &rarrlp; &looparrowright;
      ↭
      &harrw; &leftrightsquigarrow;
      ↮
      &nharr; &nleftrightarrow;
      ↰
      &lsh; &Lsh;
      ↱
      &rsh; &Rsh;
      ↲
      &ldsh;
      ↳
      &rdsh;
      ↵
      &crarr;
      ↶
      &cularr; &curvearrowleft;
      ↷
      &curarr; &curvearrowright;
      ↺
      &olarr; &circlearrowleft;
      ↻
      &orarr; &circlearrowright;
      ↼
      &lharu; &LeftVector; &leftharpoonup;
      ↽
      &lhard; &leftharpoondown; &DownLeftVector;
      ↾
      &uharr; &upharpoonright; &RightUpVector;
      ↿
      &uharl; &upharpoonleft; &LeftUpVector;
      ⇀
      &rharu; &RightVector; &rightharpoonup;
      ⇁
      &rhard; &rightharpoondown; &DownRightVector;
      ⇂
      &dharr; &RightDownVector; &downharpoonright;
      ⇃
      &dharl; &LeftDownVector; &downharpoonleft;
      ⇄
      &rlarr; &rightleftarrows; &RightArrowLeftArrow;
      ⇅
      &udarr; &UpArrowDownArrow;
      ⇆
      &lrarr; &leftrightarrows; &LeftArrowRightArrow;
      ⇇
      &llarr; &leftleftarrows;
      ⇈
      &uuarr; &upuparrows;
      ⇉
      &rrarr; &rightrightarrows;
      ⇊
      &ddarr; &downdownarrows;
      ⇋
      &lrhar; &ReverseEquilibrium; &leftrightharpoons;
      ⇌
      &rlhar; &rightleftharpoons; &Equilibrium;
      ⇍
      &nlArr; &nLeftarrow;
      ⇎
      &nhArr; &nLeftrightarrow;
      ⇏
      &nrArr; &nRightarrow;
      ⇐
      &lArr; &Leftarrow; &DoubleLeftArrow;
      ⇑
      &uArr; &Uparrow; &DoubleUpArrow;
      ⇒
      &rArr; &Rightarrow; &Implies; &DoubleRightArrow;
      ⇓
      &dArr; &Downarrow; &DoubleDownArrow;
      ⇔
      &hArr; &Leftrightarrow; &DoubleLeftRightArrow; &iff;
      ⇕
      &vArr; &Updownarrow; &DoubleUpDownArrow;
      ⇖
      &nwArr;
      ⇗
      &neArr;
      ⇘
      &seArr;
      ⇙
      &swArr;
      ⇚
      &lAarr; &Lleftarrow;
      ⇛
      &rAarr; &Rrightarrow;
      ⇝
      &zigrarr;
      ⇤
      &larrb; &LeftArrowBar;
      ⇥
      &rarrb; &RightArrowBar;
      ⇵
      &duarr; &DownArrowUpArrow;
      ⇽
      &loarr;
      ⇾
      &roarr;
      ⇿
      &hoarr;
      ∀
      &forall; &ForAll;
      ∁
      &comp; &complement;
      ∂
      &part; &PartialD;
      ∃
      &exist; &Exists;
      ∄
      &nexist; &NotExists; &nexists;
      ∅
      &empty; &emptyset; &emptyv; &varnothing;
      ∇
      &nabla; &Del;
      ∈
      &isin; &isinv; &Element; &in;
      ∉
      &notin; &NotElement; &notinva;
      ∋
      &niv; &ReverseElement; &ni; &SuchThat;
      ∌
      &notni; &notniva; &NotReverseElement;
      ∏
      &prod; &Product;
      ∐
      &coprod; &Coproduct;
      ∑
      &sum; &Sum;
      −
      &minus;
      ∓
      &mnplus; &mp; &MinusPlus;
      ∔
      &plusdo; &dotplus;
      ∖
      &setmn; &setminus; &Backslash; &ssetmn; &smallsetminus;
      ∗
      &lowast;
      ∘
      &compfn; &SmallCircle;
      √
      &radic; &Sqrt;
      ∝
      &prop; &propto; &Proportional; &vprop; &varpropto;
      ∞
      &infin;
      ∟
      &angrt;
      ∠
      &ang; &angle;
      ∡
      &angmsd; &measuredangle;
      ∢
      &angsph;
      ∣
      &mid; &VerticalBar; &smid; &shortmid;
      ∤
      &nmid; &NotVerticalBar; &nsmid; &nshortmid;
      ∥
      &par; &parallel; &DoubleVerticalBar; &spar; &shortparallel;
      ∦
      &npar; &nparallel; &NotDoubleVerticalBar; &nspar; &nshortparallel;
      ∧
      &and; &wedge;
      ∨
      &or; &vee;
      ∩
      &cap;
      ∪
      &cup;
      ∫
      &int; &Integral;
      ∬
      &Int;
      ∭
      &tint; &iiint;
      ∮
      &conint; &oint; &ContourIntegral;
      ∯
      &Conint; &DoubleContourIntegral;
      ∰
      &Cconint;
      ∱
      &cwint;
      ∲
      &cwconint; &ClockwiseContourIntegral;
      ∳
      &awconint; &CounterClockwiseContourIntegral;
      ∴
      &there4; &therefore; &Therefore;
      ∵
      &becaus; &because; &Because;
      ∶
      &ratio;
      ∷
      &Colon; &Proportion;
      ∸
      &minusd; &dotminus;
      ∺
      &mDDot;
      ∻
      &homtht;
      ∼
      &sim; &Tilde; &thksim; &thicksim;
      ∽
      &bsim; &backsim;
      ∾
      &ac; &mstpos;
      ∿
      &acd;
      ≀
      &wreath; &VerticalTilde; &wr;
      ≁
      &nsim; &NotTilde;
      ≂
      &esim; &EqualTilde; &eqsim;
      ≃
      &sime; &TildeEqual; &simeq;
      ≄
      &nsime; &nsimeq; &NotTildeEqual;
      ≅
      &cong; &TildeFullEqual;
      ≆
      &simne;
      ≇
      &ncong; &NotTildeFullEqual;
      ≈
      &asymp; &ap; &TildeTilde; &approx; &thkap; &thickapprox;
      ≉
      &nap; &NotTildeTilde; &napprox;
      ≊
      &ape; &approxeq;
      ≋
      &apid;
      ≌
      &bcong; &backcong;
      ≍
      &asympeq; &CupCap;
      ≎
      &bump; &HumpDownHump; &Bumpeq;
      ≏
      &bumpe; &HumpEqual; &bumpeq;
      ≐
      &esdot; &DotEqual; &doteq;
      ≑
      &eDot; &doteqdot;
      ≒
      &efDot; &fallingdotseq;
      ≓
      &erDot; &risingdotseq;
      ≔
      &colone; &coloneq; &Assign;
      ≕
      &ecolon; &eqcolon;
      ≖
      &ecir; &eqcirc;
      ≗
      &cire; &circeq;
      ≙
      &wedgeq;
      ≚
      &veeeq;
      ≜
      &trie; &triangleq;
      ≟
      &equest; &questeq;
      ≠
      &ne; &NotEqual;
      ≡
      &equiv; &Congruent;
      ≢
      &nequiv; &NotCongruent;
      ≤
      &le; &leq;
      ≥
      &ge; &GreaterEqual; &geq;
      ≦
      &lE; &LessFullEqual; &leqq;
      ≧
      &gE; &GreaterFullEqual; &geqq;
      ≨
      &lnE; &lneqq;
      ≩
      &gnE; &gneqq;
      ≪
      &Lt; &NestedLessLess; &ll;
      ≫
      &Gt; &NestedGreaterGreater; &gg;
      ≬
      &twixt; &between;
      ≭
      &NotCupCap;
      ≮
      &nlt; &NotLess; &nless;
      ≯
      &ngt; &NotGreater; &ngtr;
      ≰
      &nle; &NotLessEqual; &nleq;
      ≱
      &nge; &NotGreaterEqual; &ngeq;
      ≲
      &lsim; &LessTilde; &lesssim;
      ≳
      &gsim; &gtrsim; &GreaterTilde;
      ≴
      &nlsim; &NotLessTilde;
      ≵
      &ngsim; &NotGreaterTilde;
      ≶
      &lg; &lessgtr; &LessGreater;
      ≷
      &gl; &gtrless; &GreaterLess;
      ≸
      &ntlg; &NotLessGreater;
      ≹
      &ntgl; &NotGreaterLess;
      ≺
      &pr; &Precedes; &prec;
      ≻
      &sc; &Succeeds; &succ;
      ≼
      &prcue; &PrecedesSlantEqual; &preccurlyeq;
      ≽
      &sccue; &SucceedsSlantEqual; &succcurlyeq;
      ≾
      &prsim; &precsim; &PrecedesTilde;
      ≿
      &scsim; &succsim; &SucceedsTilde;
      ⊀
      &npr; &nprec; &NotPrecedes;
      ⊁
      &nsc; &nsucc; &NotSucceeds;
      ⊂
      &sub; &subset;
      ⊃
      &sup; &supset; &Superset;
      ⊄
      &nsub;
      ⊅
      &nsup;
      ⊆
      &sube; &SubsetEqual; &subseteq;
      ⊇
      &supe; &supseteq; &SupersetEqual;
      ⊈
      &nsube; &nsubseteq; &NotSubsetEqual;
      ⊉
      &nsupe; &nsupseteq; &NotSupersetEqual;
      ⊊
      &subne; &subsetneq;
      ⊋
      &supne; &supsetneq;
      ⊍
      &cupdot;
      ⊎
      &uplus; &UnionPlus;
      ⊏
      &sqsub; &SquareSubset; &sqsubset;
      ⊐
      &sqsup; &SquareSuperset; &sqsupset;
      ⊑
      &sqsube; &SquareSubsetEqual; &sqsubseteq;
      ⊒
      &sqsupe; &SquareSupersetEqual; &sqsupseteq;
      ⊓
      &sqcap; &SquareIntersection;
      ⊔
      &sqcup; &SquareUnion;
      ⊕
      &oplus; &CirclePlus;
      ⊖
      &ominus; &CircleMinus;
      ⊗
      &otimes; &CircleTimes;
      ⊘
      &osol;
      ⊙
      &odot; &CircleDot;
      ⊚
      &ocir; &circledcirc;
      ⊛
      &oast; &circledast;
      ⊝
      &odash; &circleddash;
      ⊞
      &plusb; &boxplus;
      ⊟
      &minusb; &boxminus;
      ⊠
      &timesb; &boxtimes;
      ⊡
      &sdotb; &dotsquare;
      ⊢
      &vdash; &RightTee;
      ⊣
      &dashv; &LeftTee;
      ⊤
      &top; &DownTee;
      ⊥
      &bottom; &bot; &perp; &UpTee;
      ⊧
      &models;
      ⊨
      &vDash; &DoubleRightTee;
      ⊩
      &Vdash;
      ⊪
      &Vvdash;
      ⊫
      &VDash;
      ⊬
      &nvdash;
      ⊭
      &nvDash;
      ⊮
      &nVdash;
      ⊯
      &nVDash;
      ⊰
      &prurel;
      ⊲
      &vltri; &vartriangleleft; &LeftTriangle;
      ⊳
      &vrtri; &vartriangleright; &RightTriangle;
      ⊴
      &ltrie; &trianglelefteq; &LeftTriangleEqual;
      ⊵
      &rtrie; &trianglerighteq; &RightTriangleEqual;
      ⊶
      &origof;
      ⊷
      &imof;
      ⊸
      &mumap; &multimap;
      ⊹
      &hercon;
      ⊺
      &intcal; &intercal;
      ⊻
      &veebar;
      ⊽
      &barvee;
      ⊾
      &angrtvb;
      ⊿
      &lrtri;
      ⋀
      &xwedge; &Wedge; &bigwedge;
      ⋁
      &xvee; &Vee; &bigvee;
      ⋂
      &xcap; &Intersection; &bigcap;
      ⋃
      &xcup; &Union; &bigcup;
      ⋄
      &diam; &diamond; &Diamond;
      ⋅
      &sdot;
      ⋆
      &sstarf; &Star;
      ⋇
      &divonx; &divideontimes;
      ⋈
      &bowtie;
      ⋉
      &ltimes;
      ⋊
      &rtimes;
      ⋋
      &lthree; &leftthreetimes;
      ⋌
      &rthree; &rightthreetimes;
      ⋍
      &bsime; &backsimeq;
      ⋎
      &cuvee; &curlyvee;
      ⋏
      &cuwed; &curlywedge;
      ⋐
      &Sub; &Subset;
      ⋑
      &Sup; &Supset;
      ⋒
      &Cap;
      ⋓
      &Cup;
      ⋔
      &fork; &pitchfork;
      ⋕
      &epar;
      ⋖
      &ltdot; &lessdot;
      ⋗
      &gtdot; &gtrdot;
      ⋘
      &Ll;
      ⋙
      &Gg; &ggg;
      ⋚
      &leg; &LessEqualGreater; &lesseqgtr;
      ⋛
      &gel; &gtreqless; &GreaterEqualLess;
      ⋞
      &cuepr; &curlyeqprec;
      ⋟
      &cuesc; &curlyeqsucc;
      ⋠
      &nprcue; &NotPrecedesSlantEqual;
      ⋡
      &nsccue; &NotSucceedsSlantEqual;
      ⋢
      &nsqsube; &NotSquareSubsetEqual;
      ⋣
      &nsqsupe; &NotSquareSupersetEqual;
      ⋦
      &lnsim;
      ⋧
      &gnsim;
      ⋨
      &prnsim; &precnsim;
      ⋩
      &scnsim; &succnsim;
      ⋪
      &nltri; &ntriangleleft; &NotLeftTriangle;
      ⋫
      &nrtri; &ntriangleright; &NotRightTriangle;
      ⋬
      &nltrie; &ntrianglelefteq; &NotLeftTriangleEqual;
      ⋭
      &nrtrie; &ntrianglerighteq; &NotRightTriangleEqual;
      ⋮
      &vellip;
      ⋯
      &ctdot;
      ⋰
      &utdot;
      ⋱
      &dtdot;
      ⋲
      &disin;
      ⋳
      &isinsv;
      ⋴
      &isins;
      ⋵
      &isindot;
      ⋶
      &notinvc;
      ⋷
      &notinvb;
      ⋹
      &isinE;
      ⋺
      &nisd;
      ⋻
      &xnis;
      ⋼
      &nis;
      ⋽
      &notnivc;
      ⋾
      &notnivb;
      ⌅
      &barwed; &barwedge;
      ⌆
      &Barwed; &doublebarwedge;
      ⌈
      &lceil; &LeftCeiling;
      ⌉
      &rceil; &RightCeiling;
      ⌊
      &lfloor; &LeftFloor;
      ⌋
      &rfloor; &RightFloor;
      ⌌
      &drcrop;
      ⌍
      &dlcrop;
      ⌎
      &urcrop;
      ⌏
      &ulcrop;
      ⌐
      &bnot;
      ⌒
      &profline;
      ⌓
      &profsurf;
      ⌕
      &telrec;
      ⌖
      &target;
      ⌜
      &ulcorn; &ulcorner;
      ⌝
      &urcorn; &urcorner;
      ⌞
      &dlcorn; &llcorner;
      ⌟
      &drcorn; &lrcorner;
      ⌢
      &frown; &sfrown;
      ⌣
      &smile; &ssmile;
      ⌭
      &cylcty;
      ⌮
      &profalar;
      ⌶
      &topbot;
      ⌽
      &ovbar;
      ⌿
      &solbar;
      ⍼
      &angzarr;
      ⎰
      &lmoust; &lmoustache;
      ⎱
      &rmoust; &rmoustache;
      ⎴
      &tbrk; &OverBracket;
      ⎵
      &bbrk; &UnderBracket;
      ⎶
      &bbrktbrk;
      ⏜
      &OverParenthesis;
      ⏝
      &UnderParenthesis;
      ⏞
      &OverBrace;
      ⏟
      &UnderBrace;
      ⏢
      &trpezium;
      ⏧
      &elinters;
      ␣
      &blank;
      Ⓢ
      &oS; &circledS;
      ─
      &boxh; &HorizontalLine;
      │
      &boxv;
      ┌
      &boxdr;
      ┐
      &boxdl;
      └
      &boxur;
      ┘
      &boxul;
      ├
      &boxvr;
      ┤
      &boxvl;
      ┬
      &boxhd;
      ┴
      &boxhu;
      ┼
      &boxvh;
      ═
      &boxH;
      ║
      &boxV;
      ╒
      &boxdR;
      ╓
      &boxDr;
      ╔
      &boxDR;
      ╕
      &boxdL;
      ╖
      &boxDl;
      ╗
      &boxDL;
      ╘
      &boxuR;
      ╙
      &boxUr;
      ╚
      &boxUR;
      ╛
      &boxuL;
      ╜
      &boxUl;
      ╝
      &boxUL;
      ╞
      &boxvR;
      ╟
      &boxVr;
      ╠
      &boxVR;
      ╡
      &boxvL;
      ╢
      &boxVl;
      ╣
      &boxVL;
      ╤
      &boxHd;
      ╥
      &boxhD;
      ╦
      &boxHD;
      ╧
      &boxHu;
      ╨
      &boxhU;
      ╩
      &boxHU;
      ╪
      &boxvH;
      ╫
      &boxVh;
      ╬
      &boxVH;
      ▀
      &uhblk;
      ▄
      &lhblk;
      █
      &block;
      ░
      &blk14;
      ▒
      &blk12;
      ▓
      &blk34;
      □
      &squ; &square; &Square;
      ▪
      &squf; &squarf; &blacksquare; &FilledVerySmallSquare;
      ▫
      &EmptyVerySmallSquare;
      ▭
      &rect;
      ▮
      &marker;
      ▱
      &fltns;
      △
      &xutri; &bigtriangleup;
      ▴
      &utrif; &blacktriangle;
      ▵
      &utri; &triangle;
      ▸
      &rtrif; &blacktriangleright;
      ▹
      &rtri; &triangleright;
      ▽
      &xdtri; &bigtriangledown;
      ▾
      &dtrif; &blacktriangledown;
      ▿
      &dtri; &triangledown;
      ◂
      &ltrif; &blacktriangleleft;
      ◃
      &ltri; &triangleleft;
      ◊
      &loz; &lozenge;
      ○
      &cir;
      ◬
      &tridot;
      ◯
      &xcirc; &bigcirc;
      ◸
      &ultri;
      ◹
      &urtri;
      ◺
      &lltri;
      ◻
      &EmptySmallSquare;
      ◼
      &FilledSmallSquare;
      ★
      &starf; &bigstar;
      ☆
      &star;
      ☎
      &phone;
      ♀
      &female;
      ♂
      &male;
      ♠
      &spades; &spadesuit;
      ♣
      &clubs; &clubsuit;
      ♥
      &hearts; &heartsuit;
      ♦
      &diams; &diamondsuit;
      ♪
      &sung;
      ♭
      &flat;
      ♮
      &natur; &natural;
      ♯
      &sharp;
      ✓
      &check; &checkmark;
      ✗
      &cross;
      ✠
      &malt; &maltese;
      ✶
      &sext;
      ❘
      &VerticalSeparator;
      ❲
      &lbbrk;
      ❳
      &rbbrk;
      ⟦
      &lobrk; &LeftDoubleBracket;
      ⟧
      &robrk; &RightDoubleBracket;
      ⟨
      &lang; &LeftAngleBracket; &langle;
      ⟩
      &rang; &RightAngleBracket; &rangle;
      ⟪
      &Lang;
      ⟫
      &Rang;
      ⟬
      &loang;
      ⟭
      &roang;
      ⟵
      &xlarr; &longleftarrow; &LongLeftArrow;
      ⟶
      &xrarr; &longrightarrow; &LongRightArrow;
      ⟷
      &xharr; &longleftrightarrow; &LongLeftRightArrow;
      ⟸
      &xlArr; &Longleftarrow; &DoubleLongLeftArrow;
      ⟹
      &xrArr; &Longrightarrow; &DoubleLongRightArrow;
      ⟺
      &xhArr; &Longleftrightarrow; &DoubleLongLeftRightArrow;
      ⟼
      &xmap; &longmapsto;
      ⟿
      &dzigrarr;
      ⤂
      &nvlArr;
      ⤃
      &nvrArr;
      ⤄
      &nvHarr;
      ⤅
      &Map;
      ⤌
      &lbarr;
      ⤍
      &rbarr; &bkarow;
      ⤎
      &lBarr;
      ⤏
      &rBarr; &dbkarow;
      ⤐
      &RBarr; &drbkarow;
      ⤑
      &DDotrahd;
      ⤒
      &UpArrowBar;
      ⤓
      &DownArrowBar;
      ⤖
      &Rarrtl;
      ⤙
      &latail;
      ⤚
      &ratail;
      ⤛
      &lAtail;
      ⤜
      &rAtail;
      ⤝
      &larrfs;
      ⤞
      &rarrfs;
      ⤟
      &larrbfs;
      ⤠
      &rarrbfs;
      ⤣
      &nwarhk;
      ⤤
      &nearhk;
      ⤥
      &searhk; &hksearow;
      ⤦
      &swarhk; &hkswarow;
      ⤧
      &nwnear;
      ⤨
      &nesear; &toea;
      ⤩
      &seswar; &tosa;
      ⤪
      &swnwar;
      ⤳
      &rarrc;
      ⤵
      &cudarrr;
      ⤶
      &ldca;
      ⤷
      &rdca;
      ⤸
      &cudarrl;
      ⤹
      &larrpl;
      ⤼
      &curarrm;
      ⤽
      &cularrp;
      ⥅
      &rarrpl;
      ⥈
      &harrcir;
      ⥉
      &Uarrocir;
      ⥊
      &lurdshar;
      ⥋
      &ldrushar;
      ⥎
      &LeftRightVector;
      ⥏
      &RightUpDownVector;
      ⥐
      &DownLeftRightVector;
      ⥑
      &LeftUpDownVector;
      ⥒
      &LeftVectorBar;
      ⥓
      &RightVectorBar;
      ⥔
      &RightUpVectorBar;
      ⥕
      &RightDownVectorBar;
      ⥖
      &DownLeftVectorBar;
      ⥗
      &DownRightVectorBar;
      ⥘
      &LeftUpVectorBar;
      ⥙
      &LeftDownVectorBar;
      ⥚
      &LeftTeeVector;
      ⥛
      &RightTeeVector;
      ⥜
      &RightUpTeeVector;
      ⥝
      &RightDownTeeVector;
      ⥞
      &DownLeftTeeVector;
      ⥟
      &DownRightTeeVector;
      ⥠
      &LeftUpTeeVector;
      ⥡
      &LeftDownTeeVector;
      ⥢
      &lHar;
      ⥣
      &uHar;
      ⥤
      &rHar;
      ⥥
      &dHar;
      ⥦
      &luruhar;
      ⥧
      &ldrdhar;
      ⥨
      &ruluhar;
      ⥩
      &rdldhar;
      ⥪
      &lharul;
      ⥫
      &llhard;
      ⥬
      &rharul;
      ⥭
      &lrhard;
      ⥮
      &udhar; &UpEquilibrium;
      ⥯
      &duhar; &ReverseUpEquilibrium;
      ⥰
      &RoundImplies;
      ⥱
      &erarr;
      ⥲
      &simrarr;
      ⥳
      &larrsim;
      ⥴
      &rarrsim;
      ⥵
      &rarrap;
      ⥶
      &ltlarr;
      ⥸
      &gtrarr;
      ⥹
      &subrarr;
      ⥻
      &suplarr;
      ⥼
      &lfisht;
      ⥽
      &rfisht;
      ⥾
      &ufisht;
      ⥿
      &dfisht;
      ⦅
      &lopar;
      ⦆
      &ropar;
      ⦋
      &lbrke;
      ⦌
      &rbrke;
      ⦍
      &lbrkslu;
      ⦎
      &rbrksld;
      ⦏
      &lbrksld;
      ⦐
      &rbrkslu;
      ⦑
      &langd;
      ⦒
      

      不完整,请跟踪完整文档的链接。

      【讨论】:

        【解决方案5】:

        因为:

        • 有时您正在编写 XML 数据,但不能在 XML 文件中使用 HTML 实体。
        • 因为htmlentities 替换的字符比htmlspecialchars 多。这是不必要的,会降低 PHP 脚本的效率,并且生成的 HTML 代码的可读性也会降低。

        htmlentities 仅在您的页面使用 ASCII 或 LATIN-1 而非 UTF-8 等编码并且您使用与页面不同的编码处理数据时才需要。

        【讨论】:

          【解决方案6】:

          一个小例子,我需要在一个函数中索引 2 个客户名称:

          [1] => Altisoxxce Soluxxons S.à r.l.
          [5] => Joxxson & Joxxson
          

          我最初$term = get_term_by('name', htmlentities($name), 'client'); 导致术语名称仅包含 & 数组项 (&) 但不包含重音项。但是当我将变量设置更改为htmlspecialchars 时,两者都能够运行该函数。希望这会有所帮助!

          【讨论】:

            【解决方案7】:

            htmlentities — 将所有适用的字符转换为 HTML 实体。

            htmlspecialchars — 将特殊字符转换为 HTML 实体。

            翻译对以下字符进行了翻译:

            • '&'(和号)变为'&'
            • '"'(双引号)变为 '"'当 ENT_NOQUOTES 未设置时。
            • "'"(单引号)变为''' (或')仅在设置了 ENT_QUOTES 时。
            • '
            • '>'(大于)变为'>'

            您可以查看以下代码以获取有关什么是 htmlentities 和 htmlspecialchars 的更多信息:

            https://gist.github.com/joko-wandiro/f5c935708d9c37d8940b

            【讨论】:

              【解决方案8】:

              htmlspecialchars 可以使用:

              1. 当不需要对具有其 HTML 等效项的所有字符进行编码时。

                如果您知道页面编码与文本特殊符号匹配,为什么还要使用htmlentitieshtmlspecialchars 非常简单明了,发送给客户端的代码更少。

                例如:

                echo htmlentities('<Il était une fois un être>.');
                // Output: &lt;Il &eacute;tait une fois un &ecirc;tre&gt;.
                //                ^^^^^^^^                 ^^^^^^^
                
                echo htmlspecialchars('<Il était une fois un être>.');
                // Output: &lt;Il était une fois un être&gt;.
                //                ^                 ^
                

                第二个更短,如果设置了 ISO-8859-1 字符集,不会造成任何问题。

              2. 当数据将不仅仅通过浏览器进行处理(以避免解码 HTML 实体)时,

              3. 如果输出是 XML(请参阅the answer by Artefacto)。

              【讨论】:

              • htmlspecialchars($str, ENT_QUOTES, "UTF-8") 如果您使用的 PHP 版本早于 5.4,则最好。 ENT_QUOTES 是对单引号进行编码的必要条件。
              【解决方案9】:

              当您只希望您的字符串是 XML 和 HTML 安全时,您应该使用 htmlspecialchars($strText, ENT_QUOTES)

              例如编码

              • & 到 &
              • " 到 "
              • > 到 >
              • ' 到 '

              但是,如果您的文本中还有其他字符 Unicode 或不常见的符号,那么您应该使用 htmlentities() 来确保它们在您的 HTML 页面中正确显示。

              注意事项:

              • ' 只会被 htmlspecialchars() 编码为 '如果传入了 ENT_QUOTES 选项。 '使用起来更安全‘然后’因为旧版本的 Internet Explorer 不支持实体。
              • 从技术上讲,> 不需要按照 XML 规范进行编码,但为了与

              【讨论】:

              • 问题是:因为我的文本是由用户提供的,所以我不知道那里是否有 unicode 或不常见的符号。在这种情况下我为什么要使用 htmlspecialchars ?
              【解决方案10】:

              您可能想要使用一些 Unicode 字符编码,例如 UTF-8 和 htmlspecialchars。因为如果它已经在您的字符集中,则没有任何需要为“所有 [the] 适用字符”(这是 htmlentities 根据文档所做的)生成“HTML 实体”。 p>

              【讨论】:

                【解决方案11】:

                我刚刚发现了 get_html_translation_table 函数。你将它传递给HTML_ENTITIESHTML_SPECIALCHARS,它会返回一个数组,其中包含将被编码的字符以及它们将如何编码。

                【讨论】:

                • 这在你想制作自己的功能时很有用,例如替换一些额外的字符或做其他神奇的事情。
                【解决方案12】:

                htmlspecialchars () 进行最少的编码以确保您的字符串不会被解析为 HTML。与使用 htmlentities () 对具有编码的所有内容进行绝对编码相比,这使您的字符串更具人类可读性。

                【讨论】: