function extend() {
	var options, name, src, copy, copyIsArray, clone,
		target = arguments[ 0 ] || {},
		i = 1,
		length = arguments.length,
		deep = false;

	// Handle a deep copy situation
	if ( typeof target === "boolean" ) {
		deep = target;

		// Skip the boolean and the target
		target = arguments[ i ] || {};
		i++;
	}
	// Handle case when target is a string or something (possible in deep copy)
	if ( typeof target !== "object") {
		target = {};
	}

	// Extend jQuery itself if only one argument is passed
	if ( i === length ) {
		target = this;
		i--;
	}

	for ( ; i < length; i++ ) {

		// Only deal with non-null/undefined values
		if ( ( options = arguments[ i ] ) != null ) {

			// Extend the base object
			for ( name in options ) {
				src = target[ name ];
				copy = options[ name ];

				// Prevent never-ending loop
				if ( target === copy ) {
					continue;
				}
				// Recurse if we're merging plain objects or arrays
				if ( deep && copy && ( isPlainObj(copy) ) || ( copyIsArray = Array.isArray(copy) ) )  {

					if ( copyIsArray ) {
						copyIsArray = false;
						clone = src && Array.isArray( src ) ? src : [];
					} else {
						clone = src && isPlainObj(src) ? src : {};
					}

					// Never move original objects, clone them
					target[ name ] = extend( deep, clone, copy );

				// Don't bring in undefined values
				} else if ( copy !== undefined ) {
					target[ name ] = copy;
				}
			}
		}
	}

	// Return the modified object
	return target;
};

// check object type
function isPlainObj(o) {
	return typeof o == 'object' && o.constructor == Object;
}
