<select id=test size=7 onmousedown="this.dragenable=true;this.setCapture();curOption=this.options[getIndex(this)]" onmousemove="if(this.dragenable==true)swapOption(this)" onmouseup="this.dragenable=false;this.releaseCapture();this.releaseCapture();"><option>选项一</option><option>选项二</option><option>选项三</option><option>选项四</option><option>选项五</option><option>选项六</option><option>选项七</option></select> <button onclick="up(test)">向上</button> <button onclick="down(test)">向下</button> <script> var curOption=new Option(); function up(obj) { if(obj.selectedIndex!=-1) { var obj1=obj.options(obj.selectedIndex); if (obj.selectedIndex>0) obj1.swapNode(obj1.previousSibling); } } function down(obj) { if(obj.selectedIndex!=-1) { var obj1=obj.options(obj.selectedIndex); if (obj.selectedIndex<obj.options.length-1) obj1.swapNode(obj1.nextSibling); } } function swapOption(obj) { if(curOption!=null && curOption!=obj.options[getIndex(obj)] && getIndex(obj)>-1 && getIndex(obj)<obj.size)curOption.swapNode(obj.options[getIndex(obj)]); } function getIndex(obj) { var theIndex=Math.floor((event.offsetY+2)/(obj.offsetHeight/obj.size)); if(theIndex<0)theIndex=0; else if(theIndex>obj.options.length)theIndex=obj.options.length; return theIndex; } </script>
 
提示：您可以先修改部分代码再运行