<html>
<head>
<title>查询 </title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<script type="text/javascript" src = 'jquery.js' charset ='UTF-8'></script>
<script language="JavaScript">
function dquery(){
if(($("#displayid option").length) ==0){ //$获取select的长度
alert("没有!");
return;
}else{
alert($("#displayid option").length);
alert("有!");
return;
}
//下面是一般代码，
/*
var theSel=document.getElementById("displayid");
var theSelLen=theSel.length;
if(theSelLen ==0){
alert("没有!");
return;
}else{
alert("有!");
return;
}
*/
}
</script>
</head>
<body>
<select name="displayid" id="displayid">
<option value="全部" selected>全部 </option>
</select>
<INPUT type=button value="显示个数" name="bdisplay" onClick="dquery()">
</body>
</html>
