Js navigator.onLine 獲取設備是否可以上網、連接網絡

http://zccst.iteye.com/blog/2194229

 

獲取用戶的聯網狀態

if (navigator && navigator.onLine === false) {
  alert("無法連接網絡")
}
else
{
 alert("正常上網")
}

 

監聽事件

var el = document.body;  
if (el.addEventListener) {  
   window.addEventListener("online", function () {  
     alert("online");}, true);  
   window.addEventListener("offline", function () {  
     alert("offline");}, true);  
}  
else if (el.attachEvent) {  
   window.attachEvent("ononline", function () {  
     alert("online");});  
   window.attachEvent("onoffline", function () {  
     alert("offline");});  
}  
else {  
   window.ononline = function () {  
     alert("online");};  
   window.onoffline = function () {  
     alert("offline");};  
}