Ajax http response example

As we discussed in previous tutorial that XMLHttpRequest object is used for communication between client and server.

The onreadystatechange, readyState, status and statusText properties are used in ajax http response.

Ajax object properties

Property	Description
onreadystatechange	It defines a function to be called when the readyState property changes
readyState	It holds the status of the XMLHttpRequest. XMLHttpRequest Status: 0: request not initialized 1: server connection established 2: request received 3: processing request 4: request finished and response is ready
responseText	It returns the response data as a string.
responseXML	It returns the response data as XML data.
status	It returns the status-number of a request. For example: 200: “OK” 403: “Forbidden” 404: “Not Found”
statusText	It returns the status-text (For example “OK” or “Not Found”).

Example

<!DOCTYPE html>
<html>
<body>
 
<div id="test">
<h2> Ajax http response</h2>
<button type="button" onclick="loadDocument()">Change Content</button>
</div>
 
<script>
function loadDocument() {
  var xhttp = new XMLHttpRequest();
  xhttp.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
      document.getElementById("test").innerHTML =
      this.responseText;
    }
  };
  xhttp.open("GET", "test.txt", true);
  xhttp.send();
}
</script>
 
</body>
</html>

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