改良版class选择器

getByClass: function (oParent, sClass) {//class选择器
        var aChild = oParent.getElementsByTagName('*');
        var result= [];
        var re = new RegExp('\\b' + sClass + '\\b', 'i');

        for (var i=0; i<aChild.length; i++) {
            if (re.test(sClass)) {
                result.push(aChild[i]);
            }
        }
        return result;
    }