Javascript監測網絡狀況

 
(function(){
var network = function(){
    var monitor = this;


/**
 * @param {Funcation} speedInterval
 */
var speedInterval = null;
/**
 * @param {Function} networkInterval
 */
var networkInterval = null;
/**
 * @param {Function} reNetworkInterval
 */
var reNetworkInterval = null;
var time = 5000;

/**
 * 獲取網絡連接狀態
 */
var getConnectState = function(){
    return navigator.onLine ? 1 : 0;
}; 
/**
 * 網絡中斷
 */
var disconnect = function(){
    // TODO ... 
    console.log("網速中斷");
    window.clearInterval(reNetworkInterval);
    reNetworkInterval = null;

    endSpeed();
    endNetwork();

    window.setTimeout(function(){
        reNetworkInterval = window.setInterval(function(){
            if (getConnectState() == 1) {
                window.clearInterval(reNetworkInterval);
                reNetworkInterval = null;
                startSpeed();
                startNetwork();
            } else {
                window.clearInterval(reNetworkInterval);
                reNetworkInterval = null;
                disconnect();
            }
        }, time);
    }, 2 * time);
};

/**
 * 網絡速度
 */
var speed = {
        /**
         * 網速過慢
         */
        bad : function(){

                            // TODO ... 
            console.log("網速過慢");

            window.setTimeout(function(){
                if(getConnectState() == 1) {
                    window.clearInterval(networkInterval);
                    networkInterval = null;
                    startSpeed();
                } else {
                    disconnect();
                }
            }, 2 * time);
        },
        /**
         * 網速中等
         */
        medium : function(){
                            // TODO ... 
            console.log("網速中等");
        },
        /**
         * 網速極佳
         */
        great : function(){
                            // TODO ... 
            console.log("網速極佳");
        }
};

/**
 * 開啟速度監測
 * @private
 */
var startSpeed = function(){

    window.clearInterval(speedInterval);
    speedInterval = null;
    if(getConnectState() == 1) {
        speedInterval = window.setInterval(function(){
            var start = new Date().getTime();
            if (getConnectState() == 1) {
                var img = document.getElementById("networkSpeedImage");
                if (!!!img) {
                    img = document.createElement("IMG");
                    img.id = "networkSpeedImage";
                    img.style.display = "none";
                    document.body.appendChild(img);
                }

                try {
                    img.src = "http://www.baidu.com/img/baidu_jgylogo3.gif?_t=" + new Date().getTime();
                    img.onload = function(){
                        var end = new Date().getTime();
                        var delta = end - start;
                        if (delta > 200) {
                            speed.bad();
                        } else if (delta > 100) {
                            speed.medium();
                        } else {
                            speed.great();
                        }
                    };
                } catch(e){
                    speed.bad();
                }
            } else {
                // TODO 網絡斷開
                disconnect();
            }
        }, time);
    }else {
        // TODO 網絡斷開
        disconnect();
    }
};

/**
 * 停止速度監測
 * @private
 */
var endSpeed = function(){
    window.clearInterval(speedInterval);
    speedInterval = null;
};

/**
 * 開啟網絡連接監測
 * @private
 */
var startNetwork = function(){
    if (getConnectState() == 1) {
        networkInterval = window.setInterval(function(){
            if (getConnectState() == 0) {
                disconnect();
            }
        }, time);
    } else{
        disconnect();
    }
};

/**
 * 結束網絡連接監測
 * @private 
 */
var endNetwork = function(){
    window.clearInterval(networkInterval);
    networkInterval = null;
};
/**
 * 網絡監控開始
 */
this.start = function(){
    startNetwork();
    startSpeed();
};
/**
 * 停止網絡監控
 */
this.stop = function(){
    endSpeed();
    endNetwork();
};

};
     window.network = new network();
}).call(this);
// 調用的時候,直接調用network.start();
</pre>