JavaScript（拓展特效1）

分组实现：

        var divs = document.getElementsByClassName("group");
        var cons = document.getElementsByClassName("content");

        for (var i = 0; i < divs.length; i++) {
            divs[i].onclick = function () {
                for (var j = 0; j < divs.length; j++) {
                    if (this == divs[j]) {
                        if (cons[j].style.display == "none")/*在if判断单击关闭内容*/
                            cons[j].style.display = "block";
                        else
                            cons[j].style.display = "none";
                    }
                    else {
                        cons[j].style.display = "none";
                    }
                }
            }
        }