//判断是否是IE7以下浏览器
if (navigator.appVersion.indexOf("MSIE 5.5") >= 0 || navigator.appVersion.indexOf("MSIE 6.0") >= 0
    || navigator.appVersion.indexOf("MSIE 7.0") >= 0) {

    window.attachEvent("onload", function() {
        ReloadSelectElement();

        //给所有select添加事件
        function ReloadSelectElement() {
            var s = document.getElementsByTagName("select");
            if (s.length > 0) {
                for (var i = 0, select; select = s[i]; i++) {
                    (function(e) {
                        //获得焦点时，将当前选中的项目记录下来
                        e.attachEvent("onfocus", function() {
                            e.setAttribute("current", e.selectedIndex);
                        });
                        //项目改变时，如果选中的是“无效”的项目，则返回返回前一状态
                        e.attachEvent("onchange", function() {
                            restore(e);
                        });
                    })(select)
                    //将含有disabled属性的项目“无效化”
                    emulate(select);
                }
            }
        }

        function restore(e) {
            if (e.options[e.selectedIndex].disabled) {
                e.selectedIndex = e.getAttribute("current");
            }
        }

        function emulate(e) {
            for (var i = 0, option; option = e.options[i]; i++) {
                if (option.disabled) {
                    option.style.color = "graytext";
                }
                else {
                    option.style.color = "menutext";
                }
            }
        }
    })
}