Index: offset.js
===================================================================
--- offset.js	(revision 5843)
+++ offset.js	(working copy)
@@ -82,6 +82,27 @@
 					Math.max(doc.documentElement.scrollTop,  doc.body.scrollTop));
 		}
 
+		// test whether the owner doc of our element is in an iframe
+		if ( window.document !== doc ){ 
+			var oF;
+			// some broswers support the document.defaultView and window.frameElement properties
+			if(typeof(doc.defaultView) != 'undefined' && typeof(doc.defaultView.frameElement) != 'undefined'){
+				oF = doc.defaultView.frameElement;
+			}
+			else {
+				// we aren't able to shortcut to the frame element so search for it
+				oF = findTheFrame.call(window, doc);
+				
+				// add a defaultView and frameElement
+				doc.defaultView = oF.contentWindow;
+				if(typeof(doc.defaultView.frameElement) == 'undefined') doc.defaultView.frameElement = oF;
+			}
+			
+			//if(oF === null) throw 'bad';
+			var frameOff = jQuery.fn.offset.call( [oF] );
+			add(frameOff.left, frameOff.top);
+		}
+
 		// Return an object with top and left properties
 		results = { top: top, left: left };
 	}
@@ -95,6 +116,25 @@
 		top += parseInt(t, 10) || 0;
 	}
 
+	// helper function to recursively find the iframe containing the supplied document
+	function findTheFrame(doc){
+		var toReturn = null;
+		var iframes = this.document.getElementsByTagName('iframe');
+		// loop through all the iframes in the current document
+		for(var x = 0; x < iframes.length; x++){
+			// if this is the right iframe its document will match the document we're looking for
+			if(iframes[x].contentWindow.document === doc){
+				toReturn = iframes[x];
+			}
+			else {
+				// recurse into the iframe's window and check any nested iframes
+				toReturn = findTheFrame.call(iframes[x].contentWindow, doc);
+			}
+			if(toReturn !== null) break;
+		}
+		return toReturn;
+	}
+
 	return results;
 };