Maintain Field Focus on Reload

There is a web form (only browser that this matters for is Mozilla/Firefox) that has four text fields in it. The text fields all are set up to submit on change by javascript. Required functionality is the following: when the page returns from submission, focus must return to the field that changed and caused the submit. ## Deliverables 1) Complete and fully-functional working solution will require html, javascripts, and PHP, not to exceed 150 total lines of code. 2) Deliverables must be in ready-to-run condition. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (GPL and LGPL code is allowed. 3rd party components are expressly NOT allowed.) ## Platform Only platform requirement is that this must work under a default installation of Mozilla/Firefox.