唉。真菜啊
<script language="vbscript">
sub checkform() '或FUNCTION
if len(document.form1.username.value)=0 then
alert("请输入您的用户名。")
document.form1.username.focus()
checkform=false
end if
end sub
</script>
<form name="form1" onsubmit="checkform">
怎么样才能检验提交的内容啊。。总是出现checkform类型错误