See if you can modify the code of Listings 17.1 and 17.3 to present a message to the user while waiting for an Ajax request to complete.

myAjaxLib.js-17.1

function getXMLHttpRequest()

{

try {

try {

return new ActiveXObject("Microsoft.XMLHTTP");

}

catch(e) {

return new ActiveXObject("Msxml2.XMLHTTP");

}

}

catch(e) {

return new XMLHttpRequest();

}

}

function doAjax(url, query, callback, reqtype, getxml)

{

var myreq = getXMLHttpRequest();

myreq.onreadystatechange = function()

{

while(myreq.readyState !== 4 || myreq.status !== 200){

document.getElementById("message").html("Response loading. Please wait for some time.");

}

//after it comes out of the loop, you can remove the message or display some other message.

document.getElementById("message").html("");

if(myreq.readyState == 4)

{

if(myreq.status == 200)

{

var item = myreq.responseText;

if(getxml == 1) item = myreq.responseXML;

eval(callback + '( item)');

}

}

}

if(reqtype.toUpperCase() == "POST")

{

requestPOST( url, query, myreq);

} else {

requestGET(url, query, myreq);

}

}

function requestGET(url, query, req)

{

var myRandom = parseInt(Math.random()* 99999999);

if(query == '')

{ var callUrl = url + '?rand=' + myRandom;

} else { var callUrl = url + '?' + query + '&rand=' + myRandom;

}

req.open("GET", callUrl, true);

req.send( null);

}

function requestPOST(url, query, req)

{

req.open("POST", url, true);

req.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');

req.send(query);

}

metatags.php

0) { echo $ result; } else{ echo "No keywords metatag is available."; } ?>

17.3

http://

Keywords Received: