AJAX Forms

I need 3 forms created with AJAX functionality: 1 A contact form that will check the email field for? proper email syntax? and highlight the input field in red if the email is bad, green if it is good. 2 A form that will check the form for required fields. If a required field is blank it should highlight it, once it is filled out the highlight should disapear. The submit form button should be disabled until all the required fields are filled out, a message should be displayed above the button telling a user to fill out all fields in order to submit the form. 3 A form that will ask for a user name. There should be a button beside the input that a user can click to see if the username is valid. When clicked the form should check if the username exists in a mysql database, if it does the username input should be highlighted in red and a small message stating "invalid username" shoudl be shown.