How to prevent scrolling on prepend?

I believe the most universal way to do this would be to simply measure the document height before and after you’ve modified it:

var old_height = $(document).height();  //store document height before modifications
var old_scroll = $(window).scrollTop(); //remember the scroll position

//do anything
$("p:first").prepend( "<p>I just became first</p>" );

$(document).scrollTop(old_scroll + $(document).height() - old_height); //restore "scroll position"

That way you can really do anything without the window moving away from the content you’re reading 🙂