javascript(JS)完全控制Select下拉框

 <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 onclick="setSel(3)">设置第３项为选中项</button> <button onclick="clearSel()">清空选择框</button> <button onclick="fillSel()">填充选择框</button> <button onclick="removeSel()">移除第一项</button> <button onclick="editSel()">修改第一项</button> <mce: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; } } } // --></mce:script>