禁掉浏览器的后退事件（键盘上的后退+浏览器的后退按钮）

    //禁用浏览器的backspace默认回退事件
            document.onkeypress = function (e) {
                var ev = e || window.event;//获取event对象
                var obj = ev.target || ev.srcElement;//获取事件源
                var t = obj.type || obj.getAttribute('type');//获取事件源类型
                if (ev.keyCode == 8 && t != "password" && t != "text" && t != "textarea"&& t != "number") {
                    return false;
                }
            }
            document.onkeydown = function (e) {
                var ev = e || window.event;//获取event对象
                var obj = ev.target || ev.srcElement;//获取事件源
                var t = obj.type || obj.getAttribute('type');//获取事件源类型
                if (ev.keyCode == 8 && t != "password" && t != "text" && t != "textarea"&& t != "number") {
                    return false;
                }
            }
            var counter = 0;
            if (window.history && window.history.pushState) {
                             $(window).on('popstate', function () {
                                            window.history.pushState('forward', null, '#');
                                            window.history.forward(1);
                                });
              }
  
              window.history.pushState('forward', null, '#'); //在IE中必须得有这两行
              window.history.forward(1);