 
<html> 
<head> 
<script type="text/javascript"> 
function showDiv(id){ 

document.getElementById("selectOption").style.display="block"; 
document.getElementById("selectOption").style.position="absolute"; 
document.getElementById("selectOption").style.top=document.getElementById(id).offsetTop+25; 
document.getElementById("selectOption").style.left=document.getElementById(id).offsetLeft+20; 
} 
function selectM() 
{ 
var obj = document.getElementById("mySelect"); 
alert(obj.selectedIndex); 

} 
function checkselect(objname){ 
o = document.getElementById(objname); 
t = document.getElementById("output"); 
var intvalue=""; 
for(i=0;i<o.length;i++){ 
if(o.options[i].selected){ 
intvalue+=o.options[i].value+","; 
} 
} 
t.value=intvalue.substr(0,intvalue.length-1); 
alert(intvalue); 

} 

</script> 
</head> 
<body> 

<form> 
<div id="selectOption" style='width:100px;height:50px;z-index:100;border:1px solid #0099FF;background:#cccccc;display:none;'> 
<select id="mySelect" multiple="multiple" size="4"> 
<option value='蘋果'>蘋果</option> 
<option value='桃子'>桃子</option> 
<option value='香蕉'>香蕉</option> 
<option value='桔子'>桔子</option> 
</select> 
<input type="button" onclick="checkselect('mySelect')" value="checkselect"> 
</div> 
選中的項目：<input type="text" name="output"> 
<input id="lalla" type="button" onclick="showDiv(this.id)" value="選擇"> 
<br/>
</form> 
<p>在您點擊 “選擇多個” 按鈕之前，請嘗試同時選取多個選項。在點擊 “選擇多個” 按鈕之后，請再試一次。</p>
</form> 
</body> 
</html> 