Code appears to run twice when used with Firefox

[JohnDeer]

When I run this code every time it is run in a firefox browser it seems to run twice and it records 2 entires, I have tried different machines and also different versions of FF but each time I run this. in my log file I see the following

 

Time: 27th February 2012 10:55:09 am

IP Address: 173.195.xxx.xxx

Browser: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:9.0.1) Gecko/20100101 Firefox/9.0.1

 

Time: 27th February 2012 10:55:10 am

IP Address: 173.195.xxx.xxx

Browser: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:9.0.1) Gecko/20100101 Firefox/9.0.1

 

In Chrome and IE I just get a single entry in my log.html file

 

<?php


// Create a new image instance
$im = imagecreatetruecolor(70, 20);

// Make the background white
imagefilledrectangle($im, 0, 0, 70, 20, 0xFFFFFF);

$font = imageloadfont('arial.gdf');


// Draw a text string on the image
imagestring($im, $font, 0, 0, 'Hello World', 0x000000);

// Output the image to browser
header('Content-Type: image/gif');

imagegif($im);
imagedestroy($im);



// Get server variables
$address = $_SERVER['REMOTE_ADDR'];
$referer = isset($_SERVER['HTTP_REFERER']) ?
$_SERVER['HTTP_REFERER'] : '';
$browser = $_SERVER['HTTP_USER_AGENT'];

// Do not log the full IP address replace the last 2 octets
$address = preg_replace('/\.\d+\.\d+$/', '.xxx.xxx', $address);

//Set time zone and date format
date_default_timezone_set('Australia/Sydney');
$accessTime = date("jS F Y g:i:s a");

//Open log file
$file = fopen("log.html",'a');


//write collected data to file
fwrite($file, "<b>Time:</b> $accessTime<br />");

if( $address != null)
fwrite($file,"<b>IP Address:</b> $address<br />");

if($referer != null)
fwrite($file,"<b>Referer:<b> $referer<br />");

fwrite($file,"<b>Browser:</b> $browser<hr>");


// save file and close
fclose($file);


?>

[Pikachu2000]

With Firebug installed, Firefox is known to do that. I'm not sure about any other add-ons that may cause that behavior.

[JohnDeer]

How could I set so that the script would only log one record per users ip address a day so as to stop this double logging

[litebearer]

A starting point...

http://www.tutorialspoint.com/mysql/mysql-handling-duplicates.htm

[Zane]

Update Firebug... and Firefox if you haven't already.