吴裕雄--天生自然 JAVASCRIPT开发学习：表单验证

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runoob.com)</title>
</head>
<head>
<script>
function validateForm(){
var x=document.forms["myForm"]["fname"].value;
if (x==null || x==""){
  alert("姓必须填写");
  return false;
  }
}
</script>
</head>
<body>
    
<form name="myForm" action="demo-form.php" onsubmit="return validateForm()" method="post">
姓: <input type="text" name="fname">
<input type="submit" value="提交">
</form>
    
</body>
</html>

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runoob.com)</title>
</head>
<head>
<script>
function validateForm(){
    var x=document.forms["myForm"]["email"].value;
    var atpos=x.indexOf("@");
    var dotpos=x.lastIndexOf(".");
    if (atpos<1 || dotpos<atpos+2 || dotpos+2>=x.length){
        alert("不是一个有效的 e-mail 地址");
          return false;
    }
}
</script>
</head>
<body>
    
<form name="myForm" action="demo-form.php" onsubmit="return validateForm();" method="post">
Email: <input type="text" name="email">
<input type="submit" value="提交">
</form>
    
</body>
</html>

吴裕雄--天生自然 JAVASCRIPT开发学习： 表单验证

吴裕雄--天生自然 JAVASCRIPT开发学习：表单验证