如何在当前光标位置将文本插入文本区域？

Question

我想创建一个简单的函数，将文本添加到用户光标位置的文本区域。它需要是一个干净的功能。只是基础知识。我可以弄清楚其余的。

Answer 1

使用selectionStart/selectionEnd properties of the input element（也适用于<textarea>）

function insertAtCursor(myField, myValue) {
    //IE support
    if (document.selection) {
        myField.focus();
        sel = document.selection.createRange();
        sel.text = myValue;
    }
    //MOZILLA and others
    else if (myField.selectionStart || myField.selectionStart == '0') {
        var startPos = myField.selectionStart;
        var endPos = myField.selectionEnd;
        myField.value = myField.value.substring(0, startPos)
            + myValue
            + myField.value.substring(endPos, myField.value.length);
    } else {
        myField.value += myValue;
    }
}

Answer 2

这个 sn-p 可以在几行 jQuery 1.9+ 中帮助你：http://jsfiddle.net/4MBUG/2/

$('input[type=button]').on('click', function() {
    var cursorPos = $('#text').prop('selectionStart');
    var v = $('#text').val();
    var textBefore = v.substring(0,  cursorPos);
    var textAfter  = v.substring(cursorPos, v.length);

    $('#text').val(textBefore + $(this).val() + textAfter);
});

Answer 3

为了正确的 Javascript

HTMLTextAreaElement.prototype.insertAtCaret = function (text) {
  text = text || '';
  if (document.selection) {
    // IE
    this.focus();
    var sel = document.selection.createRange();
    sel.text = text;
  } else if (this.selectionStart || this.selectionStart === 0) {
    // Others
    var startPos = this.selectionStart;
    var endPos = this.selectionEnd;
    this.value = this.value.substring(0, startPos) +
      text +
      this.value.substring(endPos, this.value.length);
    this.selectionStart = startPos + text.length;
    this.selectionEnd = startPos + text.length;
  } else {
    this.value += text;
  }
};

Answer 4

新答案：

https://developer.mozilla.org/en-US/docs/Web/API/HTMLInputElement/setRangeText

不过，我不确定浏览器是否支持此功能。

在 Chrome 81 中测试。

function typeInTextarea(newText, el = document.activeElement) {
  const [start, end] = [el.selectionStart, el.selectionEnd];
  el.setRangeText(newText, start, end, 'select');
}

document.getElementById("input").onkeydown = e => {
  if (e.key === "Enter") typeInTextarea("lol");
}

<input id="input" />
<br/><br/>
<div>Press Enter to insert "lol" at caret.</div>
<div>It'll replace a selection with the given text.</div>

旧答案：

对 Erik Pukinskis 回答的纯 JS 修改：

function typeInTextarea(newText, el = document.activeElement) {
  const start = el.selectionStart
  const end = el.selectionEnd
  const text = el.value
  const before = text.substring(0, start)
  const after  = text.substring(end, text.length)
  el.value = (before + newText + after)
  el.selectionStart = el.selectionEnd = start + newText.length
  el.focus()
}

document.getElementById("input").onkeydown = e => {
  if (e.key === "Enter") typeInTextarea("lol");
}

<input id="input" />
<br/><br/>
<div>Press Enter to insert "lol" at caret.</div>

在 Chrome 47、81 和 Firefox 76 中测试。

如果您想在同一字段中输入时更改当前选定文本的值（用于自动完成或类似效果），请将document.activeElement 作为第一个参数传递。

这不是最优雅的方法，但它非常简单。

示例用法：

typeInTextarea('hello');
typeInTextarea('haha', document.getElementById('some-id'));

Answer 5

一个简单的解决方案，适用于 firefox、chrome、opera、safari 和 edge，但可能不适用于旧的 IE 浏览器。

var target = document.getElementById("mytextarea_id")

if (target.setRangeText) {
    //if setRangeText function is supported by current browser
    target.setRangeText(data)
} else {
    target.focus()
    document.execCommand('insertText', false /*no UI*/, data);
}

setRangeText 函数允许您用提供的文本替换当前选择，或者如果没有选择，则在光标位置插入文本。据我所知只有firefox支持。

对于其他浏览器，“insertText”命令只影响当前聚焦的 html 元素，并且与setRangeText具有相同的行为

部分灵感来自article

Answer 6

我喜欢简单的 javascript，而且我通常有 jQuery。这是我根据mparkuk's 得出的结论：

function typeInTextarea(el, newText) {
    var start = el.prop("selectionStart")
    var end = el.prop("selectionEnd")
    var text = el.val()
    var before = text.substring(0, start)
    var after  = text.substring(end, text.length)
    el.val(before + newText + after)
    el[0].selectionStart = el[0].selectionEnd = start + newText.length
    el.focus()
}

$("button").on("click", function() {
    typeInTextarea($("textarea"), "some text")
    return false
})

这是一个演示：http://codepen.io/erikpukinskis/pen/EjaaMY?editors=101

Answer 7

Rab 的回答效果很好，但不适用于 Microsoft Edge，所以我也为 Edge 添加了一个小的改编：

https://jsfiddle.net/et9borp4/

function insertAtCursor(myField, myValue) {
    //IE support
    if (document.selection) {
        myField.focus();
        sel = document.selection.createRange();
        sel.text = myValue;
    }
    // Microsoft Edge
    else if(window.navigator.userAgent.indexOf("Edge") > -1) {
      var startPos = myField.selectionStart; 
      var endPos = myField.selectionEnd; 

      myField.value = myField.value.substring(0, startPos)+ myValue 
             + myField.value.substring(endPos, myField.value.length); 

      var pos = startPos + myValue.length;
      myField.focus();
      myField.setSelectionRange(pos, pos);
    }
    //MOZILLA and others
    else if (myField.selectionStart || myField.selectionStart == '0') {
        var startPos = myField.selectionStart;
        var endPos = myField.selectionEnd;
        myField.value = myField.value.substring(0, startPos)
            + myValue
            + myField.value.substring(endPos, myField.value.length);
    } else {
        myField.value += myValue;
    }
}

Answer 8

如果用户在插入文本后没有触摸输入，'input' 事件永远不会触发，value 属性也不会反映变化。因此，在以编程方式插入文本后触发输入事件很重要。专注于该领域是不够的。

以下是Snorvarg's answer 的副本，末尾带有输入触发器：

function insertAtCursor(myField, myValue) {
    //IE support
    if (document.selection) {
        myField.focus();
        sel = document.selection.createRange();
        sel.text = myValue;
    }
    // Microsoft Edge
    else if(window.navigator.userAgent.indexOf("Edge") > -1) {
      var startPos = myField.selectionStart; 
      var endPos = myField.selectionEnd; 

      myField.value = myField.value.substring(0, startPos)+ myValue 
             + myField.value.substring(endPos, myField.value.length); 

      var pos = startPos + myValue.length;
      myField.focus();
      myField.setSelectionRange(pos, pos);
    }
    //MOZILLA and others
    else if (myField.selectionStart || myField.selectionStart == '0') {
        var startPos = myField.selectionStart;
        var endPos = myField.selectionEnd;
        myField.value = myField.value.substring(0, startPos)
            + myValue
            + myField.value.substring(endPos, myField.value.length);
    } else {
        myField.value += myValue;
    }
    triggerEvent(myField,'input');
}

function triggerEvent(el, type){
  if ('createEvent' in document) {
    // modern browsers, IE9+
    var e = document.createEvent('HTMLEvents');
    e.initEvent(type, false, true);
    el.dispatchEvent(e);
  } else {
    // IE 8
    var e = document.createEventObject();
    e.eventType = type;
    el.fireEvent('on'+e.eventType, e);
  }
}

triggerEvent 函数归功于plainjs.com

w3schools.com 上有关 oninput 事件的更多信息

我在为聊天创建表情符号选择器时发现了这一点。如果用户只是选择几个表情符号并点击“发送”按钮，则用户永远不会触摸输入字段。检查 value 属性时，它始终为空，即使插入的表情符号 unicode 在输入字段中可见。事实证明，如果用户不触摸该字段，则“输入”事件永远不会触发，解决方案是像这样触发它。花了很长时间才弄清楚这个……希望它能节省一些时间。

Answer 9

function insertAtCaret(text) {
  const textarea = document.querySelector('textarea')
  textarea.setRangeText(
    text,
    textarea.selectionStart,
    textarea.selectionEnd,
    'end'
  )
}

setInterval(() => insertAtCaret('Hello'), 3000)

<textarea cols="60">Stack Overflow Stack Exchange Starbucks Coffee</textarea>

Answer 10

下面的代码是 Dmitriy Kubyshkin 对包 https://github.com/grassator/insert-text-at-cursor 的 TypeScript 改编。

/**
 * Inserts the given text at the cursor. If the element contains a selection, the selection
 * will be replaced by the text.
 */
export function insertText(input: HTMLTextAreaElement | HTMLInputElement, text: string) {
  // Most of the used APIs only work with the field selected
  input.focus();

  // IE 8-10
  if ((document as any).selection) {
    const ieRange = (document as any).selection.createRange();
    ieRange.text = text;

    // Move cursor after the inserted text
    ieRange.collapse(false /* to the end */);
    ieRange.select();

    return;
  }

  // Webkit + Edge
  const isSuccess = document.execCommand("insertText", false, text);
  if (!isSuccess) {
    const start = input.selectionStart;
    const end = input.selectionEnd;
    // Firefox (non-standard method)
    if (typeof (input as any).setRangeText === "function") {
      (input as any).setRangeText(text);
    } else {
      if (canManipulateViaTextNodes(input)) {
        const textNode = document.createTextNode(text);
        let node = input.firstChild;

        // If textarea is empty, just insert the text
        if (!node) {
          input.appendChild(textNode);
        } else {
          // Otherwise we need to find a nodes for start and end
          let offset = 0;
          let startNode = null;
          let endNode = null;

          // To make a change we just need a Range, not a Selection
          const range = document.createRange();

          while (node && (startNode === null || endNode === null)) {
            const nodeLength = node.nodeValue.length;

            // if start of the selection falls into current node
            if (start >= offset && start <= offset + nodeLength) {
              range.setStart((startNode = node), start - offset);
            }

            // if end of the selection falls into current node
            if (end >= offset && end <= offset + nodeLength) {
              range.setEnd((endNode = node), end - offset);
            }

            offset += nodeLength;
            node = node.nextSibling;
          }

          // If there is some text selected, remove it as we should replace it
          if (start !== end) {
            range.deleteContents();
          }

          // Finally insert a new node. The browser will automatically
          // split start and end nodes into two if necessary
          range.insertNode(textNode);
        }
      } else {
        // For the text input the only way is to replace the whole value :(
        const value = input.value;
        input.value = value.slice(0, start) + text + value.slice(end);
      }
    }

    // Correct the cursor position to be at the end of the insertion
    input.setSelectionRange(start + text.length, start + text.length);

    // Notify any possible listeners of the change
    const e = document.createEvent("UIEvent");
    e.initEvent("input", true, false);
    input.dispatchEvent(e);
  }
}

function canManipulateViaTextNodes(input: HTMLTextAreaElement | HTMLInputElement) {
  if (input.nodeName !== "TEXTAREA") {
    return false;
  }
  let browserSupportsTextareaTextNodes;
  if (typeof browserSupportsTextareaTextNodes === "undefined") {
    const textarea = document.createElement("textarea");
    textarea.value = "1";
    browserSupportsTextareaTextNodes = !!textarea.firstChild;
  }
  return browserSupportsTextareaTextNodes;
}

Answer 11

贴出修改后的功能供自己参考。此示例从 <select> 对象中插入一个选定项，并将插入符号放在标签之间：

//Inserts a choicebox selected element into target by id
function insertTag(choicebox,id) {
    var ta=document.getElementById(id)
    ta.focus()
    var ss=ta.selectionStart
    var se=ta.selectionEnd
    ta.value=ta.value.substring(0,ss)+'<'+choicebox.value+'>'+'</'+choicebox.value+'>'+ta.value.substring(se,ta.value.length)
    ta.setSelectionRange(ss+choicebox.value.length+2,ss+choicebox.value.length+2)
}

Answer 12

/**
 * Usage "foo baz".insertInside(4, 0, "bar ") ==> "foo bar baz"
 */
String.prototype.insertInside = function(start, delCount, newSubStr) {
    return this.slice(0, start) + newSubStr + this.slice(start + Math.abs(delCount));
};

$('textarea').bind("keydown keypress", function (event) {
    var val = $(this).val();
    var indexOf = $(this).prop('selectionStart');
    if(event.which === 13) {
        val = val.insertInside(indexOf, 0,  "<br>\n");
        $(this).val(val);
        $(this).focus();
    }
});

Answer 13

改成getElementById(myField):

function insertAtCursor(myField, myValue) {
    // IE support
    if (document.selection) {
        document.getElementById(myField).focus();
        sel = document.selection.createRange();
        sel.text = myValue;
    }
    // MOZILLA and others
    else if (document.getElementById(myField).selectionStart || document.getElementById(myField).selectionStart == '0') {
        var startPos = document.getElementById(myField).selectionStart;
        var endPos = document.getElementById(myField).selectionEnd;
        document.getElementById(myField).value =
                document.getElementById(myField).value.substring(0, startPos)
                + myValue
                + document.getElementById(myField).value.substring(endPos, document.getElementById(myField).value.length);
    } else {
        document.getElementById(myField).value += myValue;
    }
}