While javascript might be the fastest and easiest way to check for required fields, it's not a true way to verify that a required field has been filled in. It's a great way to offload some traffic by making sure that the form is filled out before sending the data across the network, but can be easily gotten around since javascript can be disabled. In order to thoroughly check that fields are filled in, server-side checking has to be done, in addition to any client-side checks.