<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gbk">
<title>JavaScript禁止提交表单</title>
<script type="text/javascript">
function getObj(id){
var Obj = document.getElementById(id).value;
return Obj;
}
function check(){
if(getObj("test")==""){
alert("文本框输入为空，不能提交表单！");
document.getElementById("test").focus;
return false;//false:阻止提交表单
}
}
</script>
</head>
<body>
<form action="index.htm" method="post" onsubmit="return check()">
<input type="text" name="test" id="test">
<input type="submit" value="提交">
</form>
</body>
</html>