Show hide icon next to input form depending on validation

I just been asked to design a small login form with 3 labels and input forms as well as a login button. The layout is pretty ready and I too开发者_如何学JAVAk the liberty of placing the warning icons next to each input forms.

Because my knowledge of jquery is very limited and that's precisely what format they asked me, I do not know how to write a validation for each form (for example nulls and minimum characters = 4) resulting in the showing and hiding of the warning icon next to it!

Please help me!

Thankyou

Kind Regards

Tiago

Have you checked out the jQuery validation plugin?

The demo page should get you started.