Mouse: Work around a bug in IE 8 where disabled inputs don't have a nodeName. Fixes #7620 - Mouse: Error in IE 8 with disabled inputs.

(cherry picked from commit 7f812f8)

Author: scottgonzalez

ui/jquery.ui.mouse.js

@@ -58,7 +58,9 @@ $.widget("ui.mouse", {
 
 		var self = this,
 			btnIsLeft = (event.which == 1),
-			elIsCancel = (typeof this.options.cancel == "string" ? $(event.target).closest(this.options.cancel).length : false);
+			// event.target.nodeName works around a bug in IE 8 with
+			// disabled inputs (#7620)
+			elIsCancel = (typeof this.options.cancel == "string" && event.target.nodeName ? $(event.target).closest(this.options.cancel).length : false);
 		if (!btnIsLeft || elIsCancel || !this._mouseCapture(event)) {
 			return true;
 		}