dext.js

/*
 * Defined Object Extension
 * May 15, 2010
 * Corey Hart @ http://www.codenothing.com
 */
/*
	dext( { str1: 'test1', str2: 'test2' }, { str1: 'overwrite', str3: 'wont-extend' } );
		=> { str1: 'overwrite', str2: 'test2' }
*/
function dext(){
	var args = Array.prototype.slice.call( arguments ), target = args[0], i = 0, l = args.length, name, copy;

	for ( ; ++i < l; ) {
		copy = args[ i ];
		for ( name in copy ) {
			if ( target.hasOwnProperty( name ) && copy.hasOwnProperty( name ) && copy[ name ] !== undefined ) {
				target[ name ] = copy[ name ];
			}
		}
	}

	return target;
}