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How to implement long connection between server and browser in ajax

php中世界最好的语言
php中世界最好的语言Original
2018-04-04 17:02:551989browse

This time I will show you how ajax realizes a long connection between the server and the browser. What are the precautions for ajax to realize a long connection between the server and the browser? The following is a practical case, let's take a look.

Sometimes, the server needs to actively push data to the browser. Ajax is used to implement this function. Please see here for details:

<script type="text/javascript" src="CSS/bootstrap-3.3.5-dist/js/bootstrap.min.js"></script>
<script type="text/javascript">
  var uid = "{$uid}";
  var i = 0;
  var timer;
  $().ready(function(){
    //打开扫码登录模态框
    $('#login').click(function(){
      //如果用户已经登录,则返回
      if(uid){ 
        return ;
      }
      //打开模态框,通过remote选项从远程加载数据
      $('#loginModel').modal({
        remote: "{:U('user/login')}"
      });
    });
     
    //模态框隐藏之后清空数据
    $("#loginModel").on("hidden.bs.modal", function() {
      $(this).removeData("bs.modal");
    });
     
    //当模态框显示出来后,通过定时返回来向服务器请求数据,定时器是每三秒请求一次服务器
    $('#loginModel').on('shown.bs.modal', function (e) {
      timer = setInterval(ajax_request, 3000);
    });
  });
   
  //ajax 请求函数,
  function ajax_request(){
    i++;
    //如果已经请求20此没有请求成功,则强制结束,给出提示信息,因为每3s调用一次,供调用20次,大概就是一分钟的时间
    if(i > 20){
      $('.login_info1').html('<span style="color:red;">登录超时,如需登录请刷新页面~</span>');
      clearInterval(timer);
      return ;
    }
     
    $.ajax({
      type: "post",
      url: "{:U('User/login_qrcode')}",
      timeout : 3000,
      data: { "scene_id": $('#scene_id').val() },
      success: function (msg){        
        if(1 == msg.status){
          $('.login_info1').html('<span style="color:#0C9;">'+msg.info+'</span>');
          setTimeout(refresh, 3000);
          return ;
        }
      },
      error: function(){
      }
    });
  }
   
  //重载页面
  function refresh(){
    location.reload();
  }
</script>
I believe you have mastered the method after reading the case in this article. For more exciting content, please pay attention to other related articles on the php Chinese website!

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Ajax and form+iframe method to implement file upload (detailed picture and text explanation) )

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