关于form表单验证未通过却提交的有关问题

关于form表单验证未通过却提交的问题

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<!--Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/--><meta http-equiv="Content-Type" content="text/html; charset=gb2312"><script language="JavaScript" type="text/javascript"> function chk_reg_input(form) {    if(form.userName.value==""){    alert("璇疯</script>