Native JavaScript implements AJAX methods _javascript tips

First for everyone to share the original JavaScript implementation of AJAX code for your reference, the specific content as follows

var getxmlhttprequest = function () {
  if window. XMLHttpRequest) {
    //main browser provides XMLHttpRequest object return
    new XMLHttpRequest ();
  } else if (window. ActiveXObject) {
    //low version of IE browser does not provide XMLHttpRequest object
    //So must use IE browser specific implementation activexobject return
    new ActiveXObject ("Microsoft.xmlhttprequest");
  }

;
var xhr = Getxmlhttprequest ();
Xhr.onreadystatechange = function () {
  console.log (xhr.readystate);
  if (xhr.readystate = = 3 && Xhr.status = =) {
    //Get successful Execute Operation
    //data in Xhr.responsetext
    Console.log (Xhr.responsetext);
  }
;
Xhr.open ("Get", "data.php", true);
Xhr.send ("");

Here's a couple of ways to use JavaScript to implement native Ajax.
You must create a XMLHttpRequest object before you implement Ajax. If you do not support the browser that created the object, you need to create ActiveXObject, as follows:

var xmlHttp; 
function Createxmlhttprequest () { 
if (window). ActiveXObject) { 
xmlHttp = new ActiveXObject ("Microsoft.XMLHTTP"); 
} else if (window. XMLHttpRequest) { 
xmlhttp=new XMLHttpRequest (); 
} 

(1) Use the XMLHTTP created above to implement the simplest Ajax GET request:

function doget (URL) { 
//Note the best use of encodeURI when passing parameter values to prevent garbled 
createxmlhttprequest (); 
Xmlhttp.open ("get", url); 
Xmlhttp.send (null); 
Xmlhttp.onreadystatechange = function () { 
if (xmlhttp.readystate = 4) && (Xmlhttp.status =)) { 
A Lert (' success '); 
} else { 
alert (' fail '); 
} 
} 

(2) Use the XMLHTTP created above to implement the simplest Ajax POST request:

function DoPost (url,data) { 
//Note the best use of encodeURI when passing parameter values to prevent garbled 
createxmlhttprequest (); 
Xmlhttp.open ("POST", url); 
Xmlhttp.setrequestheader ("Content-type", "application/x-www-form-urlencoded"); 
Xmlhttp.send (data); 
Xmlhttp.onreadystatechange = function () { 
if (xmlhttp.readystate = 4) && (Xmlhttp.status =) { 
Ale RT (' success '); 
} else { 
alert (' Fail ');}}} 
 

The above is the entire content of this article, I hope to help you learn.