Ajax Basic Operations #Programming Code Examples #NULL

Get a handle to XMLHttpRequest object

 function getAjaxObject(){

    var ajaxObject = false;

    if (window.XMLHttpRequest){

         ajaxObject = new XMLHttpRequest();

    }else if (window.ActiveXObject) {
      try{
        ajaxObject = new ActiveXObject("Msxml2.XMLHTTP");

      }catch(e){
         try{
          ajaxObject = new ActiveXObject("Microsoft.XMLHTTP");

         }catch(e){
           ajaxObject = false;

         }

      }
    }
    return ajaxObject; 

  }



use of onreadystatechange

if (ajaxObject){
//takeAction - reference to a function
   ajaxObject.onreadystatechange = takeAction; 
}



Sample code:

 var ajaxObject = getAjaxObject();

 if (ajaxObject ){
    ajaxObject.onreadystatechange = takeAction; 

    ajaxObject.open("POST","file.jsp", true);

    ajaxObject.setRequestHeader("Content-type", "application/x-www-form-urlencoded");

    ajaxObject.send("id=500&name=keith&age=18");

 }



function takeAction(ajaxObject){
  if (ajaxObject.readyState == 4) {

     //do something with the response
  }
 }


function takeAction(ajaxObject){

  if (ajaxObject.readyState == 4) {

     if (ajaxObject.status == 200 || ajaxObject.status == 304){ //response was sent succesfully 

          //do something with the response
     }
  }
 }



function takeAction(ajaxObject){
  if (ajaxObject.readyState == 4) {

     if (ajaxObject.status == 200 || 
ajaxObject.status == 304){ 
//response was sent succesfully 

          //do something with the response
          alert(ajaxObject.responseText);

     }
  }
 }






function getAjaxObject(){
    var ajaxObject = false;
    if (window.XMLHttpRequest){

         ajaxObject = new XMLHttpRequest();
    }else if (window.ActiveXObject) {

      try{
        ajaxObject = new ActiveXObject("Msxml2.XMLHTTP");

      }catch(e){
         try{
          ajaxObject = new ActiveXObject("Microsoft.XMLHTTP");

         }catch(e){
           ajaxObject = false;
         }

      }
    }
    return ajaxObject; 
  }

  function entryPoint(){

    var ajaxObject = getAjaxObject();

     if (ajaxObject ){
    ajaxObject.onreadystatechange = function(){

      takeAction(ajaxObject); 
    };
    ajaxObject.open("POST","file.jsp", true);

    ajaxObject.setRequestHeader("Content-type", "application/x-www-form-urlencoded");

    ajaxObject.send("id=500&name=keith&age=18");

 }
 }
 function takeAction(ajaxObject){
  if (ajaxObject.readyState == 4) {

     if (ajaxObject.status == 200 || ajaxObject.status == 304){
 //response was sent succesfully 

          //do something with the response
          alert(ajaxObject.responseText);

          var testDiv = document.getElementById("test");

          testDiv.innerText = ajaxObject.responseText; 

     }
  }
 }



Processing Response Data:

var data = ajaxObject.responseXML;

data.getElementsByTagName("name")

data.getElementsByTagName("name")[0]

data.getElementsByTagName("name")[0].firstChild

data.getElementsByTagName("name")[0].firstChild.nodeValue


JSON Example:

{"person":{ "name":"Keith Tang", "school":"uofm" } } 

var data = eval('('+ ajaxObject.responseText +')');
var name = data.person.name;
var school = data.person.school; 



if (ajaxObject.status == 200 || ajaxObject.status == 304){ 
//response was sent succesfully 
          //do something with the response

          alert(ajaxObject.responseText);
          var testDiv = document.getElementById("test");

          testDiv.innerHTML = ajaxObject.responseText; 

     }

Note: Brought from our old site: http://www.salearningschool.com/example_codes/ on Jan 2nd, 2017 From: http://sitestree.com/?p=10177
Categories:Programming Code Examples, NULL
Tags:NULL
Post Data:2017-01-02 16:04:23

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