small prob with fetching data from text file - php

Question

Update : success progress but still a problem : new data reloaded after refreshing the page twice it's ok to refresh the page once every 10 or 15 minutes but one ferfesh doesn't display the new data from the text file though it already contains the new data came from getData.php file
getData.php code
$connect = mysql_connect("localhost","root","");
$db = mysql_select_db("mydb",$connect);
$getTextQ = "select * from text";
$getTextR = mysql_query($getTextQ);
$path = "text/";
$myfile = $path."data.txt";
$open = fopen($myfile,"w");
while($row = mysql_fetch_array($getTextR)){
$write = fwrite($open,"<div class='slide'><h1>".$row['id']."</h1><p>".$row['desc']."</p></div>");
}
$close = fclose($open);
mysql_close($connect);
index.php code
<script src="js/jquery-1.7.1.js"></script>
<script src="js/slides.min.jquery.js"></script>
<script>
$(function(){
$.ajax({
url: 'getData.php',
type: 'POST'
});
});
var txtFile = new XMLHttpRequest();
txtFile.open("GET", "text/data.txt", true);
txtFile.onreadystatechange = function() {
if (txtFile.readyState === 4) {
if (txtFile.status === 200) {
allText = txtFile.responseText;
}
}
}
txtFile.send(null);
});
</script>
html code
<div id="mydiv" class="slides_container">
<?php $path ="text/";
$open = fopen($path."data.txt","r");
$read = fread($open,50000);
$close = fclose($open);
echo $read;
?>
</div>

Answer 1

I would not have the php file write to a text file and then read the text file; you are doing two ajax calls / requests to the server where only one is needed.
Apart from that it could lead to errors on the server when two instances try to write at the same file at the same time.
If you change your getData.php to echo out the values instead of storing them in a text file, you can simplify your javascript to:
$("#myDiv").load("getData.php");

Answer 2

.ajax is asynchronous by default. If you call .ajax first and expect it to create the text file for the .load function that is called next on the same page, set async: false in the .ajax function.
$.ajax({
url: 'getData.php',
type: 'POST',
async: false
});
Also, might be helpful to add a delay to give your server time to write the text file if that becomes an issue. I don't know how big your text file may become. Example:
$("#myDiv").delay(1000).load("text/data.txt");
Or, in the succes function as jeroen suggested:
$.ajax({
url: 'getData.php',
type: 'POST',
success: function(){
$("#myDiv").load("text/data.txt");
}
});