Multiple class names search

class_name.js

/*
 exaplme of use
 has_class(document.body, 'main');
 has_class(document.body, 'content wrapper js-on');
 has_class(document.body, 'js-on content wrapper');
*/

function has_class (node, class_names) {
	var classes, i;

	classes = class_names.replace(/^\s+|\s+$/g, '').split(/\s+/);

	if ( classes.length > 1 ) {
		for (i = 0; i < classes.length; i += 1) {
			if ( !has_class(node, classes[i]) ) {
				return false;
			}
		}
	} else {
		if ( !node.className || (' ' + node.className + ' ').indexOf(' ' + classes[0] + ' ') === -1 ) {
			return false;
		}
	}
	return true;
}