http 检测网络环境

3 月，跳不动了？>>>

    // 网络环境检测
    var ping = 1,pingObj,pingInfo = false,pingInfoL = 0;
    function startPing(){
        //
        setInterval(function () {
            if (!pingInfo){
                pingInfoL = 0;
                newRequest();
            }else {
                pingInfoL++;
            }
            if (pingInfoL > 10){
                $("#netPing").attr('class','layui-badge').text('网络极差');
            }
        },5000);
    }
    window.autotest = function(){
        $("#netPingImg").remove();
        var p = '',c;
        var n = parseFloat(ping*100);
        if (n < 200){
            p = '非常好';
            c = 'layui-bg-blue';
        }else if (n > 200 && n < 500){
            p = '一般';
            c = 'layui-bg-green';
        }else if (n > 500 && n < 1000){
            p = '差';
            c = 'layui-bg-orange';
        }else if (n > 1000){
            p = '非常差';
            c = '';
        }
        $("#netPing").attr('class','layui-badge').addClass(c).text(p);
        clearInterval(pingObj);
        pingInfo = false;
    };
    function newRequest () {
        ping = 1;
        pingObj = setInterval(function () {
            ping++;
        },100);
        pingInfo = true;
        $("#netPing").parent().append("<img id='netPingImg' src='"+window.location.origin+"/"+Math.random()+"' width='1' height='1' onerror='autotest()' style='display: none'>");
    };
    startPing();

来源：oschina

链接：https://my.oschina.net/u/3756690/blog/3211173