How do I fill form elements via onblur events? I have a user form in which I have to fill all information related to a user. I have only the email address, and I'd like all other fields to be filled when I enter the email address by using the onblur event. So I have to create a module that is called after I have filled email on the form. Via the module I will fetch all other field data.
You just need to AJAXify the form. Take a look at this article for more info on Drupal AJAX forms. To actually look up the user info you can just use the user_load_by_mail() function (more info).