how ajax js works code example

Example 1: js ajax

// For a plain JS solution, use these functions:

function _GET_REQUEST(url, response) {
  var xhttp;
  if (window.XMLHttpRequest) {
    xhttp = new XMLHttpRequest();
  } else {
    xhttp = new ActiveXObject("Microsoft.XMLHTTP");
  }

  xhttp.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
      response(this.responseText);
    }
  };

  xhttp.open("GET", url, true);
  xhttp.send();
}

function _POST_REQUEST(url, params, response) {
  var xhttp;
  if (window.XMLHttpRequest) {
    xhttp = new XMLHttpRequest();
  } else {
    xhttp = new ActiveXObject("Microsoft.XMLHTTP");
  }

  xhttp.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
      response(this.responseText);
    }
  };

  xhttp.open("POST", url, true);
  xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
  xhttp.send(params);
}

// and apply like this:
_GET_REQUEST('http://someurl', (response) => {
	// do something with variable response
});
_POST_REQUEST('http://someurl', 'paramx=y', (response) => {
	// do something with variable response
});

Example 2: JS ajax

fetch('http://example.com/movies.json')
  .then(response => response.json())
  .then(data => console.log(data));