juery 实现下拉框多选 jquery-multiselect

效果：

除了jquery，需要引用的样式和js文件：

<link rel="stylesheet" type="text/css" href="../assets/jquery.multiselect.css" />
<link rel="stylesheet" type="text/css" href="../assets/style.css" />
<link rel="stylesheet" type="text/css" href="../assets/prettify.css" />
<link href="../assets/jquery-ui.css" rel="stylesheet" />
<script src="../assets/jquery.js"></script>
<script src="../assets/jquery-ui.min.js"></script>
<script type="text/javascript" src="../assets/prettify.js"></script>
<script type="text/javascript" src="../assets/jquery.multiselect.js" charset=gb2312></script>

HTML代码：

 <select title="Basic example" multiple="multiple" name="example-basic" size="5" id="ddlConditions">
        <option value="1">Option 1</option>
        <option value="2">Option 2</option>
        <option value="3">Option 3</option>
        <option value="4">Option 4</option>
        <option value="5">Option 5</option>
        <option value="6">Option 6</option>
        <option value="7">Option 7</option>
    </select>

默认选中值1，2，3，绑定指定的选项：

  var  strcondition = '1,2,3';
        var ids = strcondition.split(',');
        if (ids != null) {
            $('#ddlConditions').val(ids);
            $('#ddlConditions').multiselect("refresh");
        }

获取选中的多个值：

首先修改jquery.multiselect.js，添加全局变量multiValues ，用来存放选项值，然后修改update方法，添加multiValues 那一行代码：

update: function() {
      var o = this.options;
      var $inputs = this.inputs;
      var $checked = $inputs.filter(':checked');
      var numChecked = $checked.length;
      var value;

      if(numChecked === 0) {
        value = o.noneSelectedText;
      } else {
        if($.isFunction(o.selectedText)) {
          value = o.selectedText.call(this, numChecked, $inputs.length, $checked.get());
        } else if(/\d/.test(o.selectedList) && o.selectedList > 0 && numChecked <= o.selectedList) {
          value = $checked.map(function() { return $(this).next().html(); }).get().join(', ');
        } else {
          value = o.selectedText.replace('#', numChecked).replace('#', $inputs.length);
        }
        multiValues = $checked.map(function () { return $(this).val(); }).get().join(',');
      }

      this._setButtonValue(value);

      return value;
    },

再添加自定义方法：

 MyValues:function(){
        return multiValues;
    },

页面使用此自定义方法，获取选中值的代码：

 if ($('input[name=multiselect_ddlConditions]:checked').length < 1)
            alert('Please Select Option');
        else {
            var strConditions = $("#ddlConditions").multiselect("MyValues");
}