Move focus to a particular field

Question

I have a button that will add show a form on the page. how can I move the focus to the first field of the form when that button is clicked?

simple example:

H

Answer 1

It might be this:

$("#newForm input:first").focus();

Answer 2

Try this:

$('input#firstfield').focus();

Answer 3

A quicker lookup would simply be.

$('#firstField').focus()

However if you removed the ID from your element then this would be better but slightly slower.

$('#newForm input:first').focus();