<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>表单验证</title>
</head>
<body>
<form name="myform" action="" onsubmit="return validateform()" method="post">
name:<input type="text" name="name"><br>
<input type="submit" value="提交">
</form>
<script type="text/javascript">
function validateform() {
var x=document.forms["myform"]["name"].value;
if (x==null || x==""){
alert("name必须填写！");
return false;
}
}
</script>
</body>
</html>