Form changes confirmation

[Jason Suplizio <su...@gmail.com>]

I have several pages containing forms that prepopulate. The user can edit
the form fields, and in the event that they leave the page w/out first
saving their edits,  I need to detect changes these changes and provide a
confirmation message like, "You've made changes to this form, are you
certain you want to exit the page w/out first saving your changes?"

I've tried several approaches - NOT including writing my own javascript -
all of which failed. Please help!!
Thanks!
Jason