w3schools ajax

JavaScript
$.ajax({
    url: 'https://example.com/your-page',
    success:function(data){
        //'data' is the value returned.
    },
    error:function(){
        alert('An error was encountered.');
    }
});//Change the text of a <div> element using an AJAX //request:
//using JQuery


$("button").click(function(){
  $.ajax({url: "demo_test.txt", success: function(result){
    $("#div1").html(result);
  }});
});



//To send a request to a server, we use the open() //and send() methods of the XMLHttpRequest object:
// Javascript


xhttp.open("GET", "ajax_info.txt", true);
xhttp.send();

//example below
<html>
<body>

<h1>The XMLHttpRequest Object</h1>

<button type="button" onclick="loadDoc()">Request data</button>

<p id="demo"></p>


<script>
function loadDoc() {
  var xhttp = new XMLHttpRequest();
  xhttp.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
      document.getElementById("demo").innerHTML = this.responseText;
    }
  };
  xhttp.open("GET", "demo_get.asp", true);
  xhttp.send();
}
</script>

</body>
</html>
Source