如何使样式化的下拉菜单可滚动？

Question

我正在使用以下样式的下拉菜单：

https://codepen.io/wallaceerick/pen/ctsCz

<select id="mounth">
    <option value="hide">-- Month --</option>
    <option value="january" rel="icon-temperature">January</option>
    <option value="february">February</option>
    <option value="march">March</option>
    <option value="april">April</option>
    <option value="may">May</option>
    <option value="june">June</option>
    <option value="july">July</option>
    <option value="august">August</option>
    <option value="september">September</option>
    <option value="october">October</option>
    <option value="november">November</option>
    <option value="december">December</option>
</select> 

问题是这个菜单不能滚动，而且它的高度没有限制。谁能告诉我如何修改css以将下拉列表的高度限制为一定数量的项目并使其像普通下拉列表一样滚动？

Answer 1

您可以将max-height 添加到.select-options 并设置overflow-y: scroll

/*
Reference: http://jsfiddle.net/BB3JK/47/
*/

$('select').each(function(){
    var $this = $(this), numberOfOptions = $(this).children('option').length;
  
    $this.addClass('select-hidden'); 
    $this.wrap('<div class="select"></div>');
    $this.after('<div class="select-styled"></div>');

    var $styledSelect = $this.next('div.select-styled');
    $styledSelect.text($this.children('option').eq(0).text());
  
    var $list = $('<ul />', {
        'class': 'select-options'
    }).insertAfter($styledSelect);
  
    for (var i = 0; i < numberOfOptions; i++) {
        $('<li />', {
            text: $this.children('option').eq(i).text(),
            rel: $this.children('option').eq(i).val()
        }).appendTo($list);
    }
  
    var $listItems = $list.children('li');
  
    $styledSelect.click(function(e) {
        e.stopPropagation();
        $('div.select-styled.active').not(this).each(function(){
            $(this).removeClass('active').next('ul.select-options').hide();
        });
        $(this).toggleClass('active').next('ul.select-options').toggle();
    });
  
    $listItems.click(function(e) {
        e.stopPropagation();
        $styledSelect.text($(this).text()).removeClass('active');
        $this.val($(this).attr('rel'));
        $list.hide();
        //console.log($this.val());
    });
  
    $(document).click(function() {
        $styledSelect.removeClass('active');
        $list.hide();
    });

});

@import url("https://fonts.googleapis.com/css?family=Lato");
body {
  font-family: Lato, Arial;
  color: #fff;
  padding: 20px;
  background-color: #e74c3c;
}

h1 {
  font-weight: normal;
  font-size: 40px;
  font-weight: normal;
  text-transform: uppercase;
}
h1 span {
  font-size: 13px;
  display: block;
  padding-left: 4px;
}

p {
  margin-top: 200px;
}
p a {
  text-transform: uppercase;
  text-decoration: none;
  display: inline-block;
  color: #fff;
  padding: 5px 10px;
  margin: 0 5px;
  background-color: #b83729;
  -moz-transition: all 0.2s ease-in;
  -o-transition: all 0.2s ease-in;
  -webkit-transition: all 0.2s ease-in;
  transition: all 0.2s ease-in;
}
p a:hover {
  background-color: #ab3326;
}

.select-hidden {
  display: none;
  visibility: hidden;
  padding-right: 10px;
}

.select {
  cursor: pointer;
  display: inline-block;
  position: relative;
  font-size: 16px;
  color: #fff;
  width: 220px;
  height: 40px;
}

.select-styled {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  background-color: #c0392b;
  padding: 8px 15px;
  -moz-transition: all 0.2s ease-in;
  -o-transition: all 0.2s ease-in;
  -webkit-transition: all 0.2s ease-in;
  transition: all 0.2s ease-in;
}
.select-styled:after {
  content: "";
  width: 0;
  height: 0;
  border: 7px solid transparent;
  border-color: #fff transparent transparent transparent;
  position: absolute;
  top: 16px;
  right: 10px;
}
.select-styled:hover {
  background-color: #b83729;
}
.select-styled:active, .select-styled.active {
  background-color: #ab3326;
}
.select-styled:active:after, .select-styled.active:after {
  top: 9px;
  border-color: transparent transparent #fff transparent;
}

.select-options {
  display: none;
  position: absolute;
  top: 100%;
  right: 0;
  left: 0;
  z-index: 999;
  margin: 0;
  padding: 0;
  list-style: none;
  background-color: #ab3326;
}
.select-options li {
  margin: 0;
  padding: 12px 0;
  text-indent: 15px;
  border-top: 1px solid #962d22;
  -moz-transition: all 0.15s ease-in;
  -o-transition: all 0.15s ease-in;
  -webkit-transition: all 0.15s ease-in;
  transition: all 0.15s ease-in;
}
.select-options li:hover {
  color: #c0392b;
  background: #fff;
}
.select-options li[rel="hide"] {
  display: none;
}

.select-options {
  max-height: 176px;
  overflow-y: scroll;
}

<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
<h1>Custom Select <span>Without Plugin</span></h1>
<!--
TO DO:
1. Add icons to List 
2. Toogle opened state
-->

<select id="mounth">
    <option value="hide">-- Month --</option>
    <option value="january" rel="icon-temperature">January</option>
    <option value="february">February</option>
    <option value="march">March</option>
    <option value="april">April</option>
    <option value="may">May</option>
    <option value="june">June</option>
    <option value="july">July</option>
    <option value="august">August</option>
    <option value="september">September</option>
    <option value="october">October</option>
    <option value="november">November</option>
    <option value="december">December</option>
</select> 

<select id="year">
    <option value="hide">-- Year --</option>
    <option value="2010">2010</option>
    <option value="2011">2011</option>
    <option value="2012">2012</option>
    <option value="2013">2013</option>
    <option value="2014">2014</option>
    <option value="2015">2015</option>
</select>

<p>See the <a href="https://codepen.io/wallaceerick/pen/fEdrz">Custom File Upload</a> demo!</p> 

Answer 2

您可以在 CSS 中设置下拉菜单的下拉内容的 overflow 属性。那么，如果你设置.dropdown-content的height，菜单会在高度受限的情况下自动允许滚动。