This is an easy to integrate shoutbox that you can use also as chat. The installation is really easily: You have just to upload one file, follow the introductions and that’s it! With just 47KB, PHP7 OOP and jQuery powered it also very fast and looks also good.

Features:

Ajax powered (no page reloads needed!)
You have to upload just ONE file to get the shoutbox running/install it.
Over 30 smilies included
Very easy to integrate into any existing (X)HTML or PHP page on your site
Cross browser support (IE9+, Firefox, Safari, Chrome, Opera, Android/iOS browser and more)
Very small: About 47KB (including jQuery, JavaScripts, images and all the rest)
PHP5 and PHP7 compatible
XSS secure
SQL-Injection protected
UTF-8 support
Shoutbox uses just 1 CSS file (+1 for mobile)
Clean PHP5 OOP code (very well commented!)
Valid HTML5
Mobile support
HTTPS support
Simple and elegant user interface
Smooth transitions
SPAM protection
Smilie support
Really simple installation
Uses standard PHP server features for extensive compatibility

Server requirements:

PHP 5.4
MySQL database
A web server (preferably Linux Apache)

Update v1.5 (08 July, 2017)

Added: PHP7 support
Updated: Improved Mobile CSS
Updated: Switched from MyISAM to InnoDB (increased performance)
Updated: Moved configuration into own file for easier changes
Updated: Optimization and reduction of CSS/JS
Updated: Latest jQuery version
Updated: Improved lossy compression of images (additional performance improvement)
Updated: Smaller cleanups of HTML
Removed: IE7, IE8 support

Update v1.4 (22 October, 2014)

Added: Mobile support
Added: Retina support
Added: HTTPS support
Added: IPv6 support
Added: Prepopulate username field over parameter (optional)
Updated: Updated code to be compatible with PHP 5.6
Updated: Switched to HTML5 (Shoutbox, Documentation, Installer)
Updated: Improved overall performance and code refactoring
Updated: Lossy compression of images (additional performance improvement)
Updated: Updated to current jQuery version (additional performance improvement)
Updated: Documentation and Installer update
Bugfix: Fixed deprecated mysql_* code
Bugfix: Reduced error possibility during SQL import
Bugfix: Expanded length of IP database field for IPv6
Removed: IE6 support

Update v1.3 (08 July, 2013)

Feature/Bugfix: Added the Shoutbox without the installer
Bugfix: Updated some CSS for latest browser support

Update v1.2 (18 December, 2011)

Added: Support for mobile devices (e.g. iPhone, Android etc.)
Bugfix: 500 server error fixed

Update v1.1 (05 November, 2009)

Several bug fixes
Added: Too long words/lines are separate in several lines
Added: Possibility to disable smilies
Added: Login-Button added
Feature: BBCode: [b][/b] (bold) added
Feature: BBCode: [i][/i] (italic) added
Feature: BBCode: [url][/url] (link) added
Feature: BBCode: [url=][/url] (link) added

Tags: Shoutbox, Chat, Ajax, PHP, jQuery, UTF-8, Mobile

If you have questions, feel free to comment or send me a mail.