This problem happens in both FF 3.0.x, and Safari, on both Windows and Mac, but not on IE7.
When I set the src of an iframe, it adds another copy of the parent document's URL to the browser history. This gives the impression of a broken back button (as the user has to click back twice to go to the previous page.) Here's a minimal test case showing that the problem isn't with jQuery, per se. It happens when I get the element using getElementbyId and change the src directly. Is there any way to avoid this back button breaking behavior? Code sample: <html> <head> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/ libs/jquery/1.3.2/jquery.js"></script> <script type="text/javascript"> $(document).ready(function() { // bypass jQuery $("#trigger").click(function() { elt = document.getElementById("targetelt"); if(elt) { elt.src = "http://google.com"; } }); // using jQuery $("#triggerJQ").click(function(e) { $("#targetelt").attr("src","http://bing.com") }); }); </script> </head> <body> <!-- use span (styled sort of like a link for fun) to rule out clicking an href as source of problem --> <span id="trigger" style="color: blue; text-decoration: underline;">hello world</span><p/> <span id="triggerJQ" style="color:blue; text-decoration: underline;">hello jQuery world</span><p/> <iframe id="targetelt" width="400" height="300"></iframe> </body> </html>