Improve handling of submit buttons when determining when to preventDefault to avoid navigation.

Only preventDefault on click events of submit buttons, not *all* events.  I want to remove
handling of submit buttons altogether (letting the form submit event be prevented, instead),
but fear that this line was put in here to solve a specific case in some buggy browser.

Author: unscriptable

lib/plugin-base/on.js

@@ -237,7 +237,7 @@ define(function (require) {
 			nodeType = node.type && node.type.toLowerCase();
 			// catch links and submit buttons/inputs in forms
 			isNavEvent = ('click' == e.type && 'A' == nodeName)
-				|| ('submit' == nodeType && node.form)
+				|| ('click' == e.type && 'submit' == nodeType && node.form)
 				|| ('submit' == e.type && 'FORM' == nodeName);
 			if (isNavEvent) {
 				preventDefaultAlways(e);