Ajax and/or PHP error - php

Question

I am using AJAX along with PHP to communicate the time a visitor spends on a page to the server where the PHP scripts writes the time spent along with other details to a text file. The AJAX script is unable to call the php script and hence the visitor details are not being logged
<script type="text/javascript">
var startTime = new Date(); //Start the clock!
window.onbeforeunload = function() //When the user leaves the page(closes the window/tab, clicks a link)...
{
var endTime = new Date(); //Get the current time.
var timeSpent = (endTime - startTime); //Find out how long it's been.
var xmlhttp; //Make a variable for a new ajax request.
if (window.XMLHttpRequest) //If it's a decent browser...
{
// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp = new XMLHttpRequest(); //Open a new ajax request.
}
else //If it's a bad browser...
{
// code for IE6, IE5
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP"); //Open a different type of ajax call.
}
xmlhttp.open("GET","ajaxphp.php?time="+timeSpent,false); //The false at the end tells ajax to use a synchronous call which wont be severed by the user leaving.
xmlhttp.send(); //Send the request and don't wait for a response.
}
</script>
This is the AJAX script
The PHP script is given below too :
<?php
$time=$_GET["time"];
$countfile = "counter.txt";
// location of site statistics.
$statsfile = "stats.txt";
// checks whether the file exist, if not then server will create it.
if (file_exists($countfile)) {
// open the counter hit file.
$fp = fopen($countfile, "r");
// reads the counter hit file and gets the size of the file.
$output = fread($fp, filesize($countfile));
// close the counter hit file.
fclose($fp);
// get the integer value of the variable.
$count = intval($output);
}
// if file is doesn't exist, the server will create the counter hit file and gives a value of zero.
else {
$count = 0;
}
// showcount function starts here.
function ShowCount() {
// declares the global variables.
global $ShowCount, $countfile, $statsfile, $count,$time;
// get the current month.
$month = date('m');
// get the current day.
$day = date('d');
// get the current year.
$year = date('Y');
// get the current hour.
$hour = date('G');
// get the current minute.
$minute = date('i');
// get the current second.
$second = date('s');
// this is the date used in the stats file
$date = "$month/$day/$year $hour:$minute:$second";
// this is the remote IP address of the user.
$remoteip = getenv("REMOTE_ADDR");
// some of the browser details of the user.
$otherinfo = getenv("HTTP_USER_AGENT");
// retrieve the last URL where the user visited before visiting the current file.
$ref = getenv("HTTP_REFERER");
// open the statistics file.
$fp = fopen($statsfile, "a");
// put the given data into the statistics file.
fputs($fp, "Remote Address: $remoteip | ");
fputs($fp, "Information: $otherinfo | ");
fputs($fp, "Date: $date | ");
fputs($fp, "Referer: $ref\n");
fputs($fp, "Time Spent: $time | ")
// close the statistics file.
fclose($fp);
// adds 1 count to the counter hit file.
$count++;
// open the counter hit file.
$fp = fopen($countfile, "w");
// write at the counter hit file.
// if the value is 34, it will be changed to 35.
fwrite($fp, $count);
// close the counter hit file.
fclose($fp);
// showcount variable is equal to count variable.
$ShowCount = $count;
// return the value of the count variable into showcount variable.
return $ShowCount;
}
// display the value in the counter hits file.
echo showcount(), " visits";
?>

Answer 1

Try the following:
Access the url ajaxphp.php?time=123456 directly with your web browser and note what happens
Use an onclick handler on a button that activates the ajax call and note what happens
Use jquery instead for the ajax and note what happens
I'm sure one of these will give you more clues to why your current setup fails.