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Sample code sharing using JavaScript to implement two select drop-down box options to move left and right

黄舟Original: 2017-03-21 14:49:072135browse

This article mainly introducesJavaScriptThe function of moving the two select drop-down box options left and right. JS realizes the movement of drop-down box elements to each other. It has certain reference value. Interested friends can For reference

I had nothing to do today and I wrote a small program using js that can move elements between two select drop-down boxes. I just started learning javascript and there are still many optimization areas.

Javascript code

<script type="text/javascript"> 
 
   
  /**选中的元素向右移动**/ 
  function moveRight() 
  { 
     
      //得到第一个select对象 
    var selectElement = document.getElementById("first"); 
    var optionElements = selectElement.getElementsByTagName("option"); 
    var len = optionElements.length; 
   
 
    if(!(selectElement.selectedIndex==-1))  //如果没有选择元素，那么selectedIndex就为-1 
    { 
       
      //得到第二个select对象 
      var selectElement2 = document.getElementById("secend"); 
   
        // 向右移动 
        for(var i=0;i<len ;i++) 
        { 
          selectElement2.appendChild(optionElements[selectElement.selectedIndex]); 
        } 
    } else 
    { 
      alert("您还没有选择需要移动的元素！"); 
    } 
  } 
   
  //移动所有的到右边 
  function moveAll() 
  { 
    //得到第一个select对象 
    var selectElement = document.getElementById("first"); 
    var optionElements = selectElement.getElementsByTagName("option"); 
    var len = optionElements.length; 
    //alert(len); 
   
    //将第一个selected中的数组翻转 
    var firstOption = new Array(); 
    for(var k=len-1;k>=0;k--) 
    { 
      firstOption.push(optionElements[k]); 
   
    } 
    var lens = firstOption.length; 
      //得到第二个select对象 
    var selectElement2 = document.getElementById("secend"); 
    for(var j=lens-1;j>=0;j--) 
    { 
      selectElement2.appendChild(firstOption[j]); 
    } 
  } 
   
  //移动选中的元素到左边 
  function moveLeft() 
  { 
    //首先得到第二个select对象 
    var selectElement = document.getElementById("secend"); 
    var optionElement = selectElement.getElementsByTagName("option"); 
    var len = optionElement.length; 
     
    //再次得到第一个元素 
    if(!(selectElement.selectedIndex==-1)) 
    { 
      var firstSelectElement = document.getElementById("first"); 
      for(i=0;i<len;i++) 
      { 
        firstSelectElement.appendChild(optionElement[selectElement.selectedIndex]);//被选中的那个元素的索引 
      } 
    }else 
    { 
      alert("您还没有选中要移动的项目!"); 
    } 
  } 
   
  //全部向左移 
  function moveAllLeft() 
  { 
    var selectElement = document.getElementById("secend"); 
    var optionElements = document.getElementsByTagName("option"); 
    var len = optionElements.length; 
    var optionEls = new Array(); 
    for(var i=len-1;i>=0;i--) 
    { 
      optionEls.push(optionElements[i]); 
    } 
    var lens = optionEls.length; 
     
    var firstSelectElement = document.getElementById("first"); 
    for(var j=lens-1;j>=0;j--) 
    { 
      firstSelectElement.appendChild(optionEls[j]); 
    } 
  } 
</script>

The above is the javascript code, and the following is the html plus css code.

Html code

<html> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 
<title>无标题文档</title> 
<style type="text/css"> 
  .select_move { margin:0px auto; width:206px; height:140px; margin-top:300px;} 
  .select_move_1 { float:left;} 
  .select_move_2 { float:left;} 
  .select_move_3 { float:left;} 
</style> 
</head> 
 
<body> 
  <p class="select_move"> 
   
    <p class="select_move_1"> 
     <select name="first" size="10" id="first" multiple="multiple"> 
      <option value="宝马">宝马</option> 
      <option value="丰田">丰田</option> 
      <option value="奥迪">奥迪</option> 
      <option value="凯迪拉克">凯迪拉克</option> 
      <option value="现代">现代</option> 
      <option value="奔驰">奔驰</option> 
      <option value="法拉利">法拉利</option> 
       
     </select> 
    </p> 
     <p class="select_move_2"> 
        <input type="button" value="------>" onclick="moveRight()"/><br /> 
        <input type="button" value="===>" onclick="moveAll()" /><br /> 
        <input type="button" value="<------" onclick="moveLeft()"/><br /> 
        <input type="button" value="<===" onclick="moveAllLeft()"/> 
     </p> 
    <p class="select_move_3"> 
       <select size="10" id="secend" multiple="multiple"> 
       </select> 
    </p> 
  </p> 
   
</body> 
</html>

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