H5实现桌面通知

<button id="button">有人想加你为好友</button>
<p id="text"></p>
;(function (){
 if(window.Notification){
 var btn = document.getElementById("button");
 var txt = document.getElementById("text");
 btn.onclick = function (){
 if(Notification.permission == "granted"){
 popNotice();
 }else if(Notification.permission != "denied"){
 Notification.requestPermission().then(function (permission){
 popNotice()
 })
 }
 };
 function popNotice(){
 if(Notification.permission == "granted"){
 var notification = new Notification("你好:",{
 body:"请问今晚有空吗",
 icon:"http://image.zhangxinxu.com/左边头像地址"
 });
 notification.onclick = function (){
 txt.innerHTML = new Date().toTimeString().split(" ")[0]+"收到信息";
 notification.close();
 }
 }
 }
 }else{
 console.log("浏览器不支持Notification");
 }
})();