fontFlex is a lightweight jQuery plugin for dynamically changing font sizes according to screen / browser width. Intended to be used with responsive or adaptive CSS layouts.
FlowType.JS is a plugin for Responsive Web Typography at its finest: font-size and line-height based on element width.
FlowType.JS is changing the font-size—and subsequently the line-height based on a specific element's width. This allows for a perfect character count per line at any screen width.