Index: jquery/src/core.js
===================================================================
--- jquery/src/core.js	(revision 5753)
+++ jquery/src/core.js	(working copy)
@@ -1201,19 +1201,25 @@
 		return ret;
 	},
 
-	map: function( elems, callback ) {
-		var ret = [];
-
+	map: function( source, callback, target ) { 
+		if( !target ) 
+			target = 'length' in source ? [ ] : { }; 
+		
+		if( 'length' in target ){ // Is it an array(-like) ? else a hash 
+			var arr = true; 
+			if( !target.concat )// Fix array-like objects, or they will fail the final concat 
+				target = jQuery.makeArray(target); 
+		} 
 		// Go through the items, translating each of the items to their
 		// new value (or values).
-		for ( var i = 0, length = elems.length; i < length; i++ ) {
-			var value = callback( elems[ i ], i );
+		jQuery.each( source , function( key, value ){ 
+			value = callback( value, key ); 
+		
+			if ( value != null ) 
+		 		target[ arr ? target.length : key ] = value; 
+		}); 
 
-			if ( value != null )
-				ret[ ret.length ] = value;
-		}
-
-		return ret.concat.apply( [], ret );
+		return arr ? target.concat.apply( [], target ) : target;
 	}
 });