javascript - 无法超出 SetInterval 返回值

Question

我遇到一个问题，无法退出此 setInterval。该函数对 PHP 文件进行 Ajax 调用。如果返回的数据有用，它将设置一个全局变量作为数据，然后它应该返回并停止调用该 PHP 文件。我目前遇到的问题是，即使它获得有用的数据，它也不会停止运行。回归好像没有什么效果。也许我只是需要另一双眼睛来关注这个问题。

setInterval(function() {

  $.ajax({
    type: "POST",
    url: 'www.example.com/test.php',
    success: function(data) {
      alert(data);
      if (data != 'None') {
        url = data;
        document.getElementById("disableddesktop").style.display = "none";
        document.getElementById("download").style.display = "block";
        document.getElementById("enableddesktopscan").style.display = "block";

        $.ajax({
          type: "POST",
          url: 'www.example.com/test.php',
          data: {
            plan: document.getElementById("plan").value,
            country: document.getElementById("firstcountry").value
          },
          success: function(data) {
            console.log(data);
            numberoforders = data;
            document.getElementById("total").innerHTML = data;
          }
        });

        return;
      }
    }
  });
}, 9000);

Answer 1

您需要clearInterval而不是return:

var interval= setInterval(function(){
  clearInterval(interval); //clear interval
}, 9000)

interval is the identifier of the repeated action you want to cancel. This ID is returned from setInterval().

所以在你的情况下应该是:

var interval = setInterval(function() {    
  $.ajax({
    type: "POST",
    url: 'www.example.com/test.php',
    success: function(data) {
      alert(data);
      if (data != 'None') {
        url = data;
        document.getElementById("disableddesktop").style.display = "none";
        document.getElementById("download").style.display = "block";
        document.getElementById("enableddesktopscan").style.display = "block";

        $.ajax({
          type: "POST",
          url: 'www.example.com/test.php',
          data: {
            plan: document.getElementById("plan").value,
            country: document.getElementById("firstcountry").value
          },
          success: function(data) {
            console.log(data);
            numberoforders = data;
            document.getElementById("total").innerHTML = data;
          }
        });

        clearInterval(interval); //clear interval      
      }
    }
  });
}, 9000);

As mplungjan said its not a good idea to use setInterval with AJAX instead use setTimeout