去除alert ,confirm上的url

    window.alert = function (name) {
            var iframe = document.createElement("IFRAME");
            iframe.style.display = "none";
            iframe.setAttribute("src", 'data:text/plain,');
            document.documentElement.appendChild(iframe);
            window.frames[0].window.alert(name);
            iframe.parentNode.removeChild(iframe);
        }
        window.confirm = function (message) {
            var iframe = document.createElement("IFRAME");
            iframe.style.display = "none";
            iframe.setAttribute("src", 'data:text/plain,');
            document.documentElement.appendChild(iframe);
            var alertFrame = window.frames[0];
            var result = alertFrame.window.confirm(message);
            iframe.parentNode.removeChild(iframe);
            return result;
        };