...Complete editing of PDF documents is possible with PDFedit. You can change raw pdf objects (for advanced users) or use many gui functions. Functionality can be easily extended using a scripting language (ECMAScript).
Cross-platform, web-based (PHP+JavaScript/EcmaScript) MPD (Music Player Daemon) client. Yet another web-client for famous Music Player Daemon. Totally in JavaScript, driven by XMLHTTPRequest (AJAX) with a small php-backend.