简单形式的AJAX验证

Question

I am trying to do client-side validation using AJAX to check for empty fields on a simple form. If the field is empty, I want to notify the user that this is not valid. The form should not submit if there are any empty fields.

What's the best way to do this?

Answer 1

There's no need to use AJAX if all you are testing for is empty fields. If you are targeting browsers that support HTML5 forms you can just do:

<input type="text" name="username" required />

If you are required to support other browsers like IE you will need to use JavaScript. Google "JavaScript form validation library" to find examples of JavaScript to do this.