Focusing first control in the form using jquery

Question

Using jquery how do I focus the first element (edit field, text area, dropdown field, etc) in the form when the page load?

Something like:

document.forms[0].elements[0].focus(); 

but using jquery.

Another requirement, don't focus the first element when the form has class="filter".

Answer 1

$('form:not(.filter) :input:visible:enabled:first').focus() 

This will select the first visible input element (<input />, <select>, <textarea>) that doesn't have the class filter in it.

Answer 2

For the background I used the script in ruby on rails app. After trying all your answer and found out they all doesn't works, With a search on google i found this snippet that works:

$(function() {   $("form:not(.filter) :input:visible:enabled:first").focus(); }); 

It turn out $('form :input:first') match the hidden input that rails insert on every form.