how ajax works javascript code example

Example 1: ajax syntax in javascript

var id = empid;

$.ajax({
    type: "POST",
    url: "../Webservices/EmployeeService.asmx/GetEmployeeOrders",
    data: "{empid: " + empid + "}",
    contentType: "application/json; charset=utf-8",
    dataType: "json",
    success: function(result){
        alert(result.d);
        console.log(result);
    }
});

Example 2: javascript ajax request

function makeRequest (method, url, data) {
  return new Promise(function (resolve, reject) {
    var xhr = new XMLHttpRequest();
    xhr.open(method, url);
    xhr.onload = function () {
      if (this.status >= 200 && this.status < 300) {
        resolve(xhr.response);
      } else {
        reject({
          status: this.status,
          statusText: xhr.statusText
        });
      }
    };
    xhr.onerror = function () {
      reject({
        status: this.status,
        statusText: xhr.statusText
      });
    };
    if(method=="POST" && data){
        xhr.send(data);
    }else{
        xhr.send();
    }
  });
}

//GET example
makeRequest('GET', "https://www.codegrepper.com/endpoint.php?param1=yoyoma").then(function(data){
              var results=JSON.parse(data);
});
//POST example
var data={"person":"john","balance":1.23};
makeRequest('POST', "https://www.codegrepper.com/endpoint.php?param1=yoyoma",data).then(function(data){
              var results=JSON.parse(data);
});