为什么出现对象不支持此属性或方法:form1.plantype.value
z9945 2003-06-09 05:29:38 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<script language="vbscript">
<!--
sub checknull
if isnull(document.form1.plantype.value) then
alert "您必须选择类型!!!"
else
form1.submit
end if
end sub
-->
</script>
</head>
<body>
<form name="form1" method="post" action="PlanAdd2.asp">
<input type="radio" name="PlanType" value="YearPlan">年
<input type="radio" name="PlanType" value="QuarterPlan" >季
<input type="radio" name="PlanType" value="MonthPlan">月
<input type="button" name="confirm" value=" 确 定 " onClick='checknull'>
</form>
</body>
</html>
为什么出现对象不支持此属性或方法:form1.plantype.value
我看别的书上都这么写的啊