Added fix for #986 (ID selector within an element that doesn't exist).

src/selector/selector.js

@@ -219,15 +219,17 @@ jQuery.extend({
 						m = re2.exec(t);
 					}
 
+					var last = ret[ret.length-1];
+
 					// Try to do a global search by ID, where we can
-					if ( m[1] == "#" && ret[ret.length-1].getElementById ) {
+					if ( m[1] == "#" && last && last.getElementById ) {
 						// Optimization for HTML document case
-						var oid = ret[ret.length-1].getElementById(m[2]);
+						var oid = last.getElementById(m[2]);
 						
 						// Do a quick check for the existence of the actual ID attribute
 						// to avoid selecting by the name attribute in IE
 						if ( jQuery.browser.msie && oid && oid.id != m[2] )
-							oid = jQuery('[@id="'+m[2]+'"]', ret[ret.length-1])[0];
+							oid = jQuery('[@id="'+m[2]+'"]', last)[0];
 
 						// Do a quick check for node name (where applicable) so
 						// that div#foo searches will be really fast