The tabindex is absolutely necessary for controlling the tab order through a really long form, from a usability and accessibility standpoint. This is probably not the preferred way to do this, you should be setting the tabindex attribute on all of your input elements in your html. Now if you work with lazy developers, that often forget to set the tabindex, you may find this to be an acceptable solution.
Quick walk through:
- The outside function is your document ready function in jQuery (explaining for those new to jQuery)
- The tabindex variable is there to keep track of the index across multiple forms on the page (another reason you may want to use something like this, if your view code is modular and split into a bunch of snippets or includes)
- The select grabs all the input and select elements on the page we then exclude the hidden input boxes
- We then set the tabindex and increment the variable