(7) Define AJAX. How to improve a webpage using AJAX? Explain with example.

Example 1: $.ajax javascript

$.ajax({
    url: 'https://example.com/your-page',
    success:function(data){
        //'data' is the value returned.
    },
    error:function(){
        alert('An error was encountered.');
    }
});

Example 2: 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
});