How do you call OnPageIndexChanging from Javascript?

I have code that when a user wants to page through a GridView, it asks them (using a JavaScript confirm) if they want to save the data from the grid. So, I'm able to get the confirm to work (with the code-behind saving function), but I'm noticing that it's not firing the OnPageIndexChanging method - which basically defeats the purpose here.I have code that when a user wants to page thro