javascript实现下拉提示选择框

本文介绍了select和sugget结合起来使用的例子，支持下拉的直接选择，也支持在下拉内容中输入过滤。
整体效果就是下面这样的：

1、首先需要引入如下文件

<link href="select2.min.css" rel="stylesheet" />
<script type="text/javascript" src="jquery-2.1.4.min.js"></script>
<script type="text/javascript" src="select2.min.js"></script> 

这里要注意jquery要放在select2的前面。
2、一些实例

<!DOCTYPE html>
<html lang="en"> 

<head>
  <meta charset="UTF-8">
  <title>Document</title>
  <link href="select2.min.css" rel="stylesheet" />
  <style type="text/css">
  .select2-dropdown {
    margin-left: 8px !important;
    margin-top: 20px !important;
  }
  </style>
</head> 

<body>
  <h1>这是单选例子</h1>
  <div class="s1-example">
    <select class="js-example-basic-single" style="width:200px">
      <optgroup label="Alaskan/Hawaiian Time Zone">
        <option value="AK">Alaska</option>
        <option value="HI">Hawaii</option>
        <option value="">请选择</option>
      </optgroup>
      <optgroup label="Pacific Time Zone">
        <option value="CA">California1111111111111111111111111111111111111111111111111</option>
        <option value="NV">Nevada</option>
        <option value="OR">Oregon</option>
        <option value="WA">Washington</option>
      </optgroup>
      <optgroup label="Mountain Time Zone">
        <option value="AZ">Arizona</option>
        <option value="CO">Colorado</option>
        <option value="ID">Idaho</option>
        <option value="MT">Montana</option>
        <option value="NE">Nebraska</option>
        <option value="NM">New Mexico</option>
        <option value="ND">North Dakota</option>
        <option value="UT">Utah</option>
        <option value="WY">Wyoming</option>
      </optgroup>
      <optgroup label="Central Time Zone">
        <option value="AL">Alabama</option>
        <option value="AR">Arkansas</option>
        <option value="IL">Illinois</option>
        <option value="IA">Iowa</option>
        <option value="KS">Kansas</option>
        <option value="KY">Kentucky</option>
        <option value="LA">Louisiana</option>
        <option value="MN">Minnesota</option>
        <option value="MS">Mississippi</option>
        <option value="MO">Missouri</option>
        <option value="OK">Oklahoma</option>
        <option value="SD">South Dakota</option>
        <option value="TX">Texas</option>
        <option value="TN">Tennessee</option>
        <option value="WI">Wisconsin</option>
      </optgroup>
      <optgroup label="Eastern Time Zone">
        <option value="CT">Connecticut</option>
        <option value="DE">Delaware</option>
        <option value="FL">Florida</option>
        <option value="GA">Georgia</option>
        <option value="IN">Indiana</option>
        <option value="ME">Maine</option>
        <option value="MD">Maryland</option>
        <option value="MA">Massachusetts</option>
        <option value="MI">Michigan</option>
        <option value="NH">New Hampshire</option>
        <option value="NJ">New Jersey</option>
        <option value="NY">New York</option>
        <option value="NC">North Carolina</option>
        <option value="OH">Ohio</option>
        <option value="PA">Pennsylvania</option>
        <option value="RI">Rhode Island</option>
        <option value="SC">South Carolina</option>
        <option value="VT">Vermont</option>
        <option value="VA">Virginia</option>
        <option value="WV">West Virginia</option>
      </optgroup>
    </select>
  </div>
  <h1>这是多选例子</h1>
  <div class="s2-example">
    <select class="js-example-basic-multiple" multiple="multiple">
      <optgroup label="Alaskan/Hawaiian Time Zone">
        <option value="AK">Alaska</option>
        <option value="HI">Hawaii</option>
        <option value="">请选择</option>
      </optgroup>
      <optgroup label="Pacific Time Zone">
        <option value="CA">California1111111111111111111111111111111111111111111111111</option>
        <option value="NV">Nevada</option>
        <option value="OR">Oregon</option>
        <option value="WA">Washington</option>
      </optgroup>
      <optgroup label="Mountain Time Zone">
        <option value="AZ">Arizona</option>
        <option value="CO">Colorado</option>
        <option value="ID">Idaho</option>
        <option value="MT">Montana</option>
        <option value="NE">Nebraska</option>
        <option value="NM">New Mexico</option>
        <option value="ND">North Dakota</option>
        <option value="UT">Utah</option>
        <option value="WY">Wyoming</option>
      </optgroup>
      <optgroup label="Central Time Zone">
        <option value="AL">Alabama</option>
        <option value="AR">Arkansas</option>
        <option value="IL">Illinois</option>
        <option value="IA">Iowa</option>
        <option value="KS">Kansas</option>
        <option value="KY">Kentucky</option>
        <option value="LA">Louisiana</option>
        <option value="MN">Minnesota</option>
        <option value="MS">Mississippi</option>
        <option value="MO">Missouri</option>
        <option value="OK">Oklahoma</option>
        <option value="SD">South Dakota</option>
        <option value="TX">Texas</option>
        <option value="TN">Tennessee</option>
        <option value="WI">Wisconsin</option>
      </optgroup>
      <optgroup label="Eastern Time Zone">
        <option value="CT">Connecticut</option>
        <option value="DE">Delaware</option>
        <option value="FL">Florida</option>
        <option value="GA">Georgia</option>
        <option value="IN">Indiana</option>
        <option value="ME">Maine</option>
        <option value="MD">Maryland</option>
        <option value="MA">Massachusetts</option>
        <option value="MI">Michigan</option>
        <option value="NH">New Hampshire</option>
        <option value="NJ">New Jersey</option>
        <option value="NY">New York</option>
        <option value="NC">North Carolina</option>
        <option value="OH">Ohio</option>
        <option value="PA">Pennsylvania</option>
        <option value="RI">Rhode Island</option>
        <option value="SC">South Carolina</option>
        <option value="VT">Vermont</option>
        <option value="VA">Virginia</option>
        <option value="WV">West Virginia</option>
      </optgroup>
    </select>
  </div>
  <h1>这是可清除有提示例子</h1>
  <div class="s3-example">
    <select class="js-example-placeholder-single" style="width:200px">
      <optgroup label="Alaskan/Hawaiian Time Zone">
        <option value="AK">Alaska</option>
        <option value="HI">Hawaii</option>
        <option value="">请选择</option>
      </optgroup>
      <optgroup label="Pacific Time Zone">
        <option value="CA">California1111111111111111111111111111111111111111111111111</option>
        <option value="NV">Nevada</option>
        <option value="OR">Oregon</option>
        <option value="WA">Washington</option>
      </optgroup>
      <optgroup label="Mountain Time Zone">
        <option value="AZ">Arizona</option>
        <option value="CO">Colorado</option>
        <option value="ID">Idaho</option>
        <option value="MT">Montana</option>
        <option value="NE">Nebraska</option>
        <option value="NM">New Mexico</option>
        <option value="ND">North Dakota</option>
        <option value="UT">Utah</option>
        <option value="WY">Wyoming</option>
      </optgroup>
      <optgroup label="Central Time Zone">
        <option value="AL">Alabama</option>
        <option value="AR">Arkansas</option>
        <option value="IL">Illinois</option>
        <option value="IA">Iowa</option>
        <option value="KS">Kansas</option>
        <option value="KY">Kentucky</option>
        <option value="LA">Louisiana</option>
        <option value="MN">Minnesota</option>
        <option value="MS">Mississippi</option>
        <option value="MO">Missouri</option>
        <option value="OK">Oklahoma</option>
        <option value="SD">South Dakota</option>
        <option value="TX">Texas</option>
        <option value="TN">Tennessee</option>
        <option value="WI">Wisconsin</option>
      </optgroup>
      <optgroup label="Eastern Time Zone">
        <option value="CT">Connecticut</option>
        <option value="DE">Delaware</option>
        <option value="FL">Florida</option>
        <option value="GA">Georgia</option>
        <option value="IN">Indiana</option>
        <option value="ME">Maine</option>
        <option value="MD">Maryland</option>
        <option value="MA">Massachusetts</option>
        <option value="MI">Michigan</option>
        <option value="NH">New Hampshire</option>
        <option value="NJ">New Jersey</option>
        <option value="NY">New York</option>
        <option value="NC">North Carolina</option>
        <option value="OH">Ohio</option>
        <option value="PA">Pennsylvania</option>
        <option value="RI">Rhode Island</option>
        <option value="SC">South Carolina</option>
        <option value="VT">Vermont</option>
        <option value="VA">Virginia</option>
        <option value="WV">West Virginia</option>
      </optgroup>
    </select>
  </div>
  <div class="s4-example">
    <select class="js-example-placeholder-multiple" multiple="multiple" style="width:400px">
      <optgroup label="Alaskan/Hawaiian Time Zone">
        <option value="AK">Alaska</option>
        <option value="HI">Hawaii</option>
        <option value="">请选择</option>
      </optgroup>
      <optgroup label="Pacific Time Zone">
        <option value="CA">California1111111111111111111111111111111111111111111111111</option>
        <option value="NV">Nevada</option>
        <option value="OR">Oregon</option>
        <option value="WA">Washington</option>
      </optgroup>
      <optgroup label="Mountain Time Zone">
        <option value="AZ">Arizona</option>
        <option value="CO">Colorado</option>
        <option value="ID">Idaho</option>
        <option value="MT">Montana</option>
        <option value="NE">Nebraska</option>
        <option value="NM">New Mexico</option>
        <option value="ND">North Dakota</option>
        <option value="UT">Utah</option>
        <option value="WY">Wyoming</option>
      </optgroup>
      <optgroup label="Central Time Zone">
        <option value="AL">Alabama</option>
        <option value="AR">Arkansas</option>
        <option value="IL">Illinois</option>
        <option value="IA">Iowa</option>
        <option value="KS">Kansas</option>
        <option value="KY">Kentucky</option>
        <option value="LA">Louisiana</option>
        <option value="MN">Minnesota</option>
        <option value="MS">Mississippi</option>
        <option value="MO">Missouri</option>
        <option value="OK">Oklahoma</option>
        <option value="SD">South Dakota</option>
        <option value="TX">Texas</option>
        <option value="TN">Tennessee</option>
        <option value="WI">Wisconsin</option>
      </optgroup>
      <optgroup label="Eastern Time Zone">
        <option value="CT">Connecticut</option>
        <option value="DE">Delaware</option>
        <option value="FL">Florida</option>
        <option value="GA">Georgia</option>
        <option value="IN">Indiana</option>
        <option value="ME">Maine</option>
        <option value="MD">Maryland</option>
        <option value="MA">Massachusetts</option>
        <option value="MI">Michigan</option>
        <option value="NH">New Hampshire</option>
        <option value="NJ">New Jersey</option>
        <option value="NY">New York</option>
        <option value="NC">North Carolina</option>
        <option value="OH">Ohio</option>
        <option value="PA">Pennsylvania</option>
        <option value="RI">Rhode Island</option>
        <option value="SC">South Carolina</option>
        <option value="VT">Vermont</option>
        <option value="VA">Virginia</option>
        <option value="WV">West Virginia</option>
      </optgroup>
    </select>
  </div>
  <h1>这是直接使用js对象初始化的例子</h1>
  <div>
    <select class="js-example-data-array" style="width:200px"></select>
  </div>
  <div>
    <select class="js-example-data-array-selected" style="width:200px">
      <option value="2" selected="selected">duplicate</option>
    </select>
  </div> 

  <script type="text/javascript" src="jquery-2.1.4.min.js"></script>
  <script type="text/javascript" src="select2.min.js"></script>
  <script type="text/javascript">
  $(document).ready(function() {
    $(".js-example-basic-single").select2(); //单选
    $(".js-example-basic-multiple").select2(); //多选 

    $(".js-example-placeholder-single").select2({ //允许清除
      placeholder: "Select a state", //默认提示语
      allowClear: true
    }); 

    $(".js-example-placeholder-multiple").select2({
      placeholder: "Select a state" //默认提示语
    }); 

    var data = [{
      id: 0,
      text: 'enhancement'
    }, {
      id: 1,
      text: 'bug'
    }, {
      id: 2,
      text: 'duplicate'
    }, {
      id: 3,
      text: 'invalid'
    }, {
      id: 4,
      text: 'wontfix'
    }]; 

    $(".js-example-data-array").select2({
      data: data
    }) 

    $(".js-example-data-array-selected").select2({
      data: data
    }) 

  });
  </script>
</body> 

</html> 

3、效果
效果1

效果2

还有一些其它的内容，比如果说支持通过ajax查找来填充，支持input等，想要了解更多内容的朋友请阅读相关文章。