title: How can I enhance the functionality of a page whose source I shouldn't modify?
body: <p>A friend of mine uses a web-app for work related purposes. 
  The app's built using PHP/MySQL , and while it has some JavaScript to make it easier to work with, it's not user friendly enough, and with a bit of extra JS, a lot of stuff could be automated.</p>
  
  <p>I would like to enhance that app, but I'd like to not have to modify the original server-side code. To do this, all I could think of was Greasemonkey. Is this the only way to do it, or am I missing out something? I'd also like to be able to use a modern JS framework, like jQuery.</p>
  
  <p>EDIT: I should tell you what improvements I want to make. There are a lot of fields on the page, so autocompletion would really help a lot. This will be used for data entering, so AJAX may be used for some error checking as well.</p>