为Html 的Select 加一个提示语和输入方法

xieyj（原作）

<Html>
<Head>
<script LANGUAGE="Javascript">
<!--
//定义 select 原值
var oldValue,oldText;
//select下拉框的onkeydown事件，修改下拉框的值
function catch_keydown(sel)
{
switch(event.keyCode)
{
case 13: //回车键
   event.returnValue = false;
   break;
case 27: //Esc键
   sel.options[sel.selectedIndex].text = oldText;
   sel.options[sel.selectedIndex].value = oldValue;
   event.returnValue = false;
   break;
case 8: //空格健
   var s = sel.options[sel.selectedIndex].text;
   s = s.substr(0,s.length-1);
   if (sel.options[sel.selectedIndex].value==sel.options[sel.selectedIndex].text)
   {
    sel.options[sel.selectedIndex].value=s;
    sel.options[sel.selectedIndex].text=s;
   }
   event.returnValue = false;
   break;
}
if (!event.returnValue && sel.onchange)
sel.onchange(sel)
}

//select下拉框的onkeypress事件，修改下拉框的值
function catch_press(sel){
if(sel.selectedIndex>=0){
var s = sel.options[sel.selectedIndex].text + String.fromCharCode(event.keyCode);
if (sel.options[sel.selectedIndex].value==sel.options[sel.selectedIndex].text)
{
sel.options[sel.selectedIndex].value=s;
sel.options[sel.selectedIndex].text=s;
}
event.returnValue = false;
if (!event.returnValue && sel.onchange)
sel.onchange(sel)
}
}

//select下拉框的onfocus事件，保存下拉框原来的值
function catch_focus(sel) {
oldText = sel.options[sel.selectedIndex].value;
oldValue = sel.options[sel.selectedIndex].value;
}

//恢复select下拉列表当前选中的值
function LoadSelect(obj,value)
{
for (var i=0; i< obj.options.length; i++)
if (obj.options[i].value == value)
{
obj.selectedIndex = i;
break;
}
}

//select 选择框鼠标上移时提示选择的内容
function selMouseOver(obj)
{
with (document.all.div_hint)
{
innerText = obj.options[obj.selectedIndex].text;
if (innerText.length > 0)
{
   innerText = " " + innerText + " ";
   style.display = "block";
   style.left = event.clientX + 16;
   style.top = event.clientY;
}
}
}

//select 选择框鼠标移开时消失
function selMouseOut(obj)
{
with (document.all.div_hint)
{
style.display = "none"
}
}
//-->
</script>
</Head>
<Body>

<select style='width:130px;z-index:-1' name='tmpSel' onmouseover=selMouseOver(this) onmouseout=selMouseOut(this) onkeydown=catch_keydown(this) onkeypress=catch_press(this) onfocus=catch_focus(this)>
<option value=''></option>
</select>

<div id=div_hint style="font-size:12px;color:red;display:none;position:absolute; z-index:2; top:200;background-color: #F7F7F7; layer-background-color: #0099FF; border: 1px #9c9c9c solid;filter:Alpha(style=0,opacity=80,finishOpacity=100);"></div>
</Body>
</Html>