Is there any way in Firebug to set a breakpoint in an external .js file that a page links to so that it can be stepped through?
(I suspect I've found a bug in jQuery and I want to be able to step through jQuery as it's handling events to see what it's doing.)
Not sure if I understand the question, but I don't think Firebug treats external javascript any differently than internal one. Just go to the "script" tab, select the .js file in the drop down list and set your breakpoint.
来源：https://stackoverflow.com/questions/579920/can-firebug-set-breakpoints-in-external-javascript-files