function isMobile() {
            var userAgentInfo = navigator.userAgent;
            var mobileAgents = [ "Android", "iPhone", "SymbianOS", "Windows Phone", "iPad","iPod"];
            var mobile_flag = false;
            //根据userAgent判断是否是手机
            for (var v = 0; v < mobileAgents.length; v++) {
                if (userAgentInfo.indexOf(mobileAgents[v]) > 0) {
                    mobile_flag = true;
                    break;
                }
            }
             var screen_width = window.screen.width;
             var screen_height = window.screen.height;    
             //根据屏幕分辨率判断是否是手机
             if(screen_width < 500 && screen_height < 800){
                 mobile_flag = true;
             }
             return mobile_flag;
        }