src/browser/base/S.History.js
function(e){
			var history=S.History, current = history.getFragment();
			if(OLD_IE && current == history.fragment && history.iframe) current = history.getFragment(history.getHash(history.iframe));
			if(current == history.fragment) return false;
			if(history.iframe) history.navigate(current);
			history.loadUrl();
		}
function(e){
			var history=S.History, current = history.getFragment();
			if(OLD_IE && current == history.fragment && history.iframe) current = history.getFragment(history.getHash(history.iframe));
			if(current == history.fragment) return false;
			if(history.iframe) history.navigate(current);
			history.loadUrl();
		}
Checks the current URL to see if it has changed, and if it has, calls `loadUrl`, normalizing across the hidden iframe.