foo.js

var ifr = Y.Node.create('<iframe id="'+frameId+'" src="javascript:0" name="ibframe" scrollbar="no" frameborder="no"></iframe>');
			tgtNode.appendChild(ifr);
			
			var ifrNode = Y.Node.getDOMNode(ifr);
			var ifrNodeDoc = ifrNode.contentWindow.document;
			var content = this.get("content");
			// for Firefox
			ifrNodeDoc.open().close();
			
			this.set("innerFrameYUI",
				YUI({
					win:ifrNode.contentWindow,
					doc:ifrNode.contentWindow.document
				})
			);