封装 class 类 js

封装 class 类 js

function getClass (cls) {
            //判断浏览器是否支持
            if (document.getElementsByClassName) {
                return document.getElementsByClassName(cls);
            }
            //兼容写法
            var arr = [];
            var divs = document.getElementsByTagName("*");
            for (var i=0; i<divs.length; i++)
            {
                var arrlist = divs[i].className.split(" ");
                for (var j= 0,len=arrlist.length; j<len; j++ ) {
                    if (arrlist[j] == cls) {
                        arr.push(divs[i]);
                    }
                }
            }
            return arr;
        }

 限定一个 id 中查找 className

function getClass (cls,id) {
            //判断浏览器是否支持
            if (document.getElementsByClassName) {
                if (id) {
                    var objId = document.getElementById(id);
                    return objId.getElementsByClassName(cls);
                } else {
                    return document.getElementsByClassName(cls);
                }
            }
            //兼容写法
            var arr = [];
            if (id) {
                var objId = document.getElementById(id);
                var divs = objId.getElementsByTagName("*");
            } else {
                var divs = document.getElementsByTagName("*");
            }

            for (var i=0; i<divs.length; i++)
            {
                var arrlist = divs[i].className.split(" ");
                for (var j= 0,len=arrlist.length; j<len; j++ ) {
                    if (arrlist[j] == cls) {
                        arr.push(divs[i]);
                    }
                }
            }
            return arr;
        }