자바스크립트가 네트워크를 감지하는 방법

<script type="text/javascript">
	// 通过window.navigator.onLine 来检测网络是否可用
    alert(window.navigator.onLine); // 返回的是一个bool值(true表示已连接,false表示未连接)
</script>

<script type="text/javascript">
    window.addEventListener("offline",function(){alert("网络连接恢复");})
    window.addEventListener("online",function(){alert("网络连接中断");})
</script>

<script type="text/javascript">
    window.ononline=function(){alert("网络连接恢复");}
    window.onoffline=function(){alert("网络连接中断");}
</script>

<script type="text/javascript">
	var el = document.body;  
	if (el.addEventListener) {  
	   window.addEventListener("online", function () {  
	     alert("网络连接恢复");}, true);  
	   window.addEventListener("offline", function () {  
	     alert("网络连接中断");}, true);  
	}  
	else if (el.attachEvent) {  
	   window.attachEvent("ononline", function () {  
	     alert("网络连接恢复");});  
	   window.attachEvent("onoffline", function () {  
	     alert("网络连接中断");});  
	}  
	else {  
	   window.ononline = function () {  
	     alert("网络连接恢复");};  
	   window.onoffline = function () {  
	     alert("网络连接中断");};  
	}  
</script>

<script type="text/javascript">
	$.ajax({
	  url: &#39;https://sug.so.360.cn/suggest&#39;,
	  dataType:&#39;jsonp&#39;,
	  success: function(result){
	    console.log(&#39;网络正常&#39;)
	  }, 
	  error: function(result){
	    console.log(&#39;网络异常&#39;)
	  }
	});
</script>