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I'm started create simple Chat with Ajax!
I'm finish basic chat, but they have a problem.
When i activate my function timer from <body onload="getDataFromServer()"> then always a got old XML from server. Under this i think i got XML with data witch was there when i'm inicialize me chat page, although in meantime i set new data to database.
When i send new data to server, server insert this data to database and return me again "old" XML.
If i turn off timer function, then everything is ok, but always i must click send button to get data from server, and this is not dinamic.
And i'm now lost!
In this moment chat has two files, index.php and getdata.php.
Files content:
index.php
=============================================
<html>
<head>
<title> Qisland CHAT </title>
</head>
<script type="text/javascript">
function provjera(){
var ime=document.getElementById("nick").value.length;
if (ime>0) {
document.getElementById("forma1").submit();
}
else {
document.getElementById("nick").focus();
}
}
// KOD ZA AJAX
// ** kreiranje XMLHTTP objekta preko kojeg se vrši promet Ajax-om
function kreirajObjekt(){
var req;
if (window.XMLHttpRequest)
req = new XMLHttpRequest();
else if (window.ActiveXObject)
req = new ActiveXObject("Microsoft.XMLHTTP");
else
alert ("Greška kod kreiranja objekta za Ajax!");
return req;
}
// kreiranje varijable koja če predstavljat objekt XMLHttpRequest
var http = kreirajObjekt();
// kreiranje funkcije za slanje podataka serveru
// tip=1 ako se šalju podaci u bazu ili tip=0 ako se samo traže podaci iz baze
function slanjeZahtjeva(tip){
if (tip==1)
http.open('get', "getdata.php?speekarea="+document.getElementById(" speekarea").value+"&nickname="+
document.getElementById("nickname").value+"&tip="+ tip, true);
else
http.open('get', "getdata.php?speekarea=0&nickname=0$tip="+tip, true);
http.onreadystatechange = upravljanjeZahtjevom;
http.send(null);
}
// kreiranje funkcije koja če upravljati primljenim podacima od servera
function upravljanjeZahtjevom(){
if (http.readyState==4 && http.status == 200){
var pristiglo = http.responseText;
if (pristiglo)
document.getElementById("chatarea").value = pristiglo;
}
}
//////////////////////////////
//////// Critical part
/////////////////////////////
// TIMER koji če periodički skidat podatke sa servera
function getDataFromServer(){
slanjeZahtjeva('0');
setTimeout('getDataFromServer()', 500);
}
////////////////////////////////
////////////////////////////////
////////////////////////////////
</script>
<?php
$ime = $_POST["nick"];
if (isset($ime)){
echo "
<body bgcolor=\"#6060cc\" onload=\"getDataFromServer()\">>
<h1><center><font color=\"#ddaaaa\"> Wellcom Qisland Chat!</font></center></h1><br><br>
<form>Nick: " . $ime . "<br>
<a href=\"http://tutorials.awardspace.com/Chat/index.php\"> Back </a><br><hr>
<input type=\"hidden\" name=\"nickname\" value=\"" . $ime . "\">
<textarea rows=\"25\" cols=\"100\" id=\"chatarea\" name=\"chatarea\" readOnly=\"true\"></textarea><br>
<input type=\"text\" size=\"120\" id=\"speekarea\" name=\"speekarea\">
<input type=\"button\" id=\"senddata\" name=\"senddata\" value=\"Send\" onClick=\"slanjeZahtjeva('1')\">
</form>";
}
else{
echo "
<body bgcolor=\"#6060cc\">
<h1><center><font color=\"#ddaaaa\"> Wellcom Qisland Chat!</font></center></h1><br><br>
<form action=\"index.php\" method=\"POST\" id=\"forma1\">
Enter Nick: <input type=\"text\" id=\"nick\" name=\"nick\" maxLength=\"20\" size=\"22\">
<input type=\"button\" id=\"submit_form\" value=\"Uđi na chat\" onClick=\"provjera()\">";
}
echo "
</form>
</body>
</html>";
?>
getdata.php
================================================
<?php
$var1 = $_GET["nickname"];
$var2 = $_GET["speekarea"];
if ($_GET["tip"]){
$var3 = date("H:i");
$var4 = date("Y-n-j");
$baza = mysql_connect('#*$!', 'xxx', 'xxx') or die ('Server sa bazom nije dostupan');
mysql_select_db('xxx') or die ('Greska kod spajanja na bazu podataka');
$rez = mysql_query("insert into chat values('$var1', '$var2', '$var3', '$var4')") or die ("Greska kod upisa u bazu (kat već postoji)");
mysql_close($baza);
}
$baza = mysql_connect('xxx', 'xxx', 'xxx') or die ('Server sa bazom nije dostupan');
mysql_select_db('xxx') or die ('Greska kod spajanja na bazu podataka');
$rez = mysql_query('select * from chat');
$redovi = mysql_num_rows($rez);
for ($i=0; $i<$redovi; $i++){
$nick = mysql_result($rez, $i, 0);
$red = mysql_result($rez, $i, 1);
echo $nick . ": " . $red . "\n";
}
mysql_close($baza);
?>
So if anybody see or know where i'm wrong...
I hope somebody know what is wrong whit this.
Thanks!
Bye!
it sounds like you are getting a cached page.
I agree. As a standard, I always use the valueOf() method of a new date object as the last argument for any server call...
var d = new Date();
var url = "page.php?arg1=bla&d="+d.valueOf();
- JS
Using the POST method in stead of the GET method with ajax doesn't have this problem ...
Using the GET method isn't a good idea any way! every one can see what data is communicated between the client and the server (passwords included!)
