<HTML>
<HEAD>
<SCRIPT LANGUAGE="JavaScript">
function check()
{
var jieguo="返回true";
if (document.myform.yeah.value=="")
{
jieguo="返回false";
}
alert(jieguo);
return false;
}
</SCRIPT>
</HEAD>
<BODY>
<form name="myform" method="post" onSubmit="return check();">
<select name="yeah">
<option value="">空值</option>
<option value="1">第一项</option>
<option value="2">第二项</option>
<option value="3">第三项</option>
</select>
<input type="submit">
</form>
</BODY>
</HTML>
[此贴子已经被作者于2005-6-24 9:18:21编辑过]