jQuery is a fantastic javascript library with excellent CSS selector capabilities and DOM manipulation. It's light-weight and really fast. Prototype is an excellent all-purpose library with many great utility features, including string manipulation, enumerable arrays and hashes. I love using jQuery for its speed and simplicity, but I miss Prototype's utilities. Luckily, jQuery is very extensible with its versatile plugin system. $.string is a plugin which aims to provide Prototype's string manipulation functions to jQuery.