The browser.version check was causing browsers with undetected userag…

…ents to die. This, at least, makes it fail gracefully.

src/jquery/jquery.js

@@ -1811,7 +1811,7 @@ new function() {
 
 	// Figure out what browser is being used
 	jQuery.browser = {
-		version: b.match(/.+(?:rv|it|ra|ie)[\/: ]([\d.]+)/)[1],
+		version: (b.match(/.+(?:rv|it|ra|ie)[\/: ]([\d.]+)/) || [])[1],
 		safari: /webkit/.test(b),
 		opera: /opera/.test(b),
 		msie: /msie/.test(b) && !/opera/.test(b),