ajax跨域访问报错 ajax跨域访问报错501的解决办法

$.ajax({
      type: "POST",
    url: "http://192.168.1.202/sensordata.php",

    contentType:'application/json; charset=utf-8',
    data: JSON.stringify(ajaxPostData),
    dataType:'json',
    success: function(data){
      //On ajax success do this
      console.info("success.");
      if (data["status"] == "ok"){
        alert("Settings is Ok. The Machine is rebooting.");
      }
    },
    error: function(xhr, ajaxOptions, thrownError) {
      //On error do this
      console.info("error.");
      if (xhr.status == 200) {

        alert(ajaxOptions);
      }
      else {
        alert(xhr.status);
        alert(thrownError);
      }
    }
  });