我需要JavaScript表单验证吗？

Question

I'm working on some forms for a Website. Currently I have the usual HTML Browser check (with "required"-tag and patterns and stuff in the inputs), I check the values in a JavaScript before submitting and I do a server-sided check of the data after submitting.

Everything works fine, even if I have only one of them enabled, but it seems a little bit overkill to me, so my question is if I can just leave the Javascript check out? Of course I need to keep the server chek :D

Looking forward to your answers!

Answer 1

You must always validate input at serverside. Javascript is optional and it just to make life of your users easier. Your users get better experience. That's it.

Answer 2

All modern browsers support the HTML5 form field attributes. As you are using those, you may skip the JS validation.

Answer 3

To expand a little on the current answers:

Server side validation is always required, you mentioned that.

HTML and Javascript validation are used for different things.

The HTML required tag can be used to check a form's fields are not blank before a form submission.

Javascript validation allows you to be far more flexible with what you want to validate and when . However, it requires more work because it's not as simple as a required tag.

With Javascript you can do far more. Some examples:

• Validation that occurs as soon as a user starts to type
• Have the box highlight a different colour
• Show an error message
• Have a big red cross appear next to invalid fields or a big green one next to valid ones
• Spin your page around when the user enters something invalid. (don't actually do that)
• etc.

Also note browser support for the required tag.