html运行实例（js_validation_js）-搜寻教程库

代码示例：（标识：js_validation_js）

<!DOCTYPE html>
<html>
<head>
<script>
function validateForm() {
  let x = document.forms["myForm"]["fname"].value;
  if (x == "") {
    alert("Name must be filled out");
    return false;
  }
}
</script>
</head>
<body>

<h1>JavaScript 验证</h1>

<form name="myForm" action="/index/demo/form_current.html" onsubmit="return validateForm()" method="post">
  Name: <input type="text" name="fname">
  <input type="submit" value="Submit">
</form>

</body>
</html>