JS对Select(客户端下拉列表框的控制)

<select id="mysel" name="mysel">
  <option value="1">1 xxxxxxxxxx</option>
  <option value="2">2 yyyyyyyyyy</option>
  <option value="3">3 zzzzzzzzzz</option>
  <option value="4">4 wwwwwwwwww</option>
</select>
<button /> <button /> <button /> <button /> <button /> <script type="text/javascript">
    function setSel(str){
        with(document.all){   
            for(var i=0;i<mysel.options.length;i++){               
                if (mysel.options[i].value==str){
                    mysel.selectedIndex=i;
                    break;
                }
            }           
        }
    }
function clearSel(){
        with(document.all){   
            mysel.options.length=0;
        }
    }
function fillSel(){
        with(document.all){
            mysel.options.length=0;
            mysel.options[0] = new Option("1 xxxxxxxxxx","1");
            mysel.options[1] = new Option("2 yyyyyyyyyy","2");
            mysel.options[2] = new Option("3 zzzzzzzzzz","3");
            mysel.options[3] = new Option("4 wwwwwwwwww","4");
            mysel.options[4] = new Option("5 aaaaaaaaaa","5");
          mysel.selectedIndex = 4;
        }
    }
function removeSel(){
        with(document.all){
            mysel.remove(0);
            if (mysel.options.length>0){
                mysel.selectedIndex=0;
            }
        }
    }
 function editSel(){
        with(document.all){
            if (mysel.options.length>0){
                mysel.options[0] = new Option("这是新的第一项","new Value")
                mysel.selectedIndex=0;
            }
        }
}