关于下拉框的onchange事件和onclick选择value值。

下拉框的onchange事件和onclick，一般最好都选择onchange事件，onclick可能会不兼容有些浏览器。

下面是代码：

<!DOCTYPE html>
<html lang="en">
<head>
   <meta charset="UTF-8">
   <title>选择</title>
   <script src="js/lib/jquery/v1.12.3/jquery-1.12.3.js"></script>
   <style>
      #one {
         border: 1px solid salmon;
         width: 40px;
         height: 100px;
         position: absolute;
         left: 20px;
      }
      #two {
         border: 1px solid salmon;
         width: 40px;
         height: 100px;
         position: absolute;
         left: 61px;
      }
      #three {
         border: 1px solid salmon;
         width: 40px;
         height: 100px;
         position: absolute;
         left: 102px;
      }
   </style>
   <script>
   function showlist(optvalue){
       if(optvalue=="1"){
         $( "#select1" ).show();
         $( "#select2" ).hide();
         $( "#select3" ).hide();
      }
      else if(optvalue=="2"){
         $( "#select2" ).show();
         $( "#select1" ).hide();
         $( "#select3" ).hide();
      }
      else{
         $( "#select3" ).show();
         $( "#select1" ).hide();
         $( "#select2" ).hide();
      }
   }
   </script>
</head>
<body>
      <div id="one">
         <select name="" id="select1" onchange="showlist(this.value)">
            <option value="1"></option>
            <option value="2"></option>
            <option value="3"></option>
         </select>
      </div>
      <div id="two">
         <select name="" id="select2"
               style="display: none"
               onchange="showlist(this.value)">
            <option value="1"></option>
            <option value="2"></option>
            <option value="3"></option>
         </select>
      </div>
      <div id="three">
         <select name="" id="select3"
               style="display: none"
               onchange="showlist(this.value)">
            <option value="1"></option>
            <option value="2"></option>
            <option value="3"></option>
         </select>
      </div>
   <script>
   $( document ).ready( function()
   {
      //这是onclick事件可能有些不兼容，不推荐使用
      /*var sel = $( "select" );
      var option = sel.children();
      console.log( option );
      for( var i = 0; i < option.length; i++ )
      {
         option[ i ].onclick = function()
         {
            alert( this.value );
            if( this.value ==1 )
            {
               $( "#select1" ).show();
               $( "#select2" ).hide();
               $( "#select3" ).hide();
            }
            else
               if( this.value ==2 )
               {
                  $( "#select2" ).show();
                  $( "#select1" ).hide();
                  $( "#select3" ).hide();
               }
               else
               {
                  $( "#select3" ).show();
                  $( "#select1" ).hide();
                  $( "#select2" ).hide();
               }
         }
      }*/
   } );
   </script>
</body>
</html>