//检测浏览器类型：ie、火狐、谷歌、safari
        function getbrowsername() {
            var useragent = navigator ? navigator.useragent.tolowercase() : "other";
            if (useragent.indexof("chrome") > -1) return "chrome";
            else if (useragent.indexof("safari") > -1) return "safari";
            else if (useragent.indexof("msie") > -1 || useragent.indexof("trident") > -1) return "ie";
            else if (useragent.indexof("firefox") > -1) return "firefox";
            return useragent;
        }

        //针对ie返回activexobject
        function getactivexobject(name) {
            try {
                return new activexobject(name);
            } catch (e) {
            }
        }

        //针对除了ie之外浏览器
        function getnavigatorplugin(name) {
            for (key in navigator.plugins) {
                var plugin = navigator.plugins[key];
                if (plugin.name == name) return plugin;
            }
        }

        //获取adobe reader插件信息
        function getpdfplugin() {
            if (getbrowsername() == 'ie') {
                //
                // load the activex control
                // acropdf.pdf is used by version 7 and later
                // pdf.pdfctrl is used by version 6 and earlier
                return getactivexobject('acropdf.pdf') || getactivexobject('pdf.pdfctrl');
            }
            else {
                return getnavigatorplugin('adobe acrobat') || getnavigatorplugin('chrome pdf viewer') || getnavigatorplugin('webkit built-in pdf');
            }
        }

        //判断插件是否安装
        function isacrobatinstalled() {
            return !!getpdfplugin();
        }
        function getacrobatversion() {
            try {
                var plugin = getpdfplugin();
                if (getbrowsername() == 'ie') {
                    var versions = plugin.getversions().split(',');
                    var latest = versions[0].split('=');
                    return parsefloat(latest[1]);
                }
                if (plugin.version) return parseint(plugin.version);
                return plugin.name;
            }
            catch (e) {
                return null;
            }
        }