<html>
<body>
<form action="tryjs_submitpage.htm" onsubmit="return myFunction()">
姓名 (最大 10 个字符): <input type="text" id="fname" size="20"><br>
年龄 (从 1 到 100): <input type="text" id="age" size="20"><br>
E-mail: <input type="text" id="email" size="20"><br>
<br>
<input type="submit" value="Submit">
</form>
<script>
function myFunction() {
var at = document.getElementById("email").value.indexOf("@");
var age = document.getElementById("age").value;
var fname = document.getElementById("fname").value;
submitOK = "true";
if (fname.length>10) {
alert("姓名不能超过 10 个字符");
submitOK = "false";
}
if (isNaN(age)||age<1||age>100) {
alert("年龄范围为 1 到 100");
submitOK = "false";
}
if (at==-1) {
alert("不合法的 e-mail!");
submitOK = "false";
}
if (submitOK=="false") {
return false;
}
}
</script>
</body>
</html>