Using prototypes is slow

I did a benchmark test, and it turns out using prototypes makes a function call twice slower in Google Chrome, and in Firefox, it is 4-5 times slower!!! So, when you're writing a function library for strings where speed is of concern, then you should declare functions like this :

function truncate(str, length, pruneStr) { ... } // this is just an example

DO NOT USE PROTOTYPES. They needlessly slow down the execution of your code!

There's an alternative library that doesn't use prototypes.
http://wzsn.net/zLib.htm