title: Catching the specific Javascript code being executed onClick
body: <p>I am working on a site that has loads of legacy Javascript and jQuery includes and there is no documentation to show what is happening when.</p>
  <p>I have a specific problem to fix and I cannot find the relevant code that is being executed when a button is clicked. To save me from trawling through (and making sense of) hundreds of lines of legacy script, is there a feature, possibly in Firebug, that will identify what script is being executed when I click on a button?</p>