http request send and post javascript example

Example 1: javascript send post data with ajax

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();
    }
  });
}

//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);
});

Example 2: http request javascript

function httpGetAsync(url, callback) {
  var xmlHttp = new XMLHttpRequest();
  xmlHttp.onreadystatechange = function() { 
    if (xmlHttp.readyState == 4 && xmlHttp.status == 200)
      callback(xmlHttp.responseText);
  }
  xmlHttp.open("GET", url, true); // true for asynchronous 
  xmlHttp.send(null);
}