FitText makes flexible font-sizes jQuery plugin for making sure a text fits into a defined element. Use this plugin on your fluid or responsive layout to achieve scalable headlines that fill the width of a parent element. It was made for headlines only, you shouldn’t use it on paragraph text.
It auto-updates the font-size in accordance with the width of an element wrapping it and guarantees a non-broken layout (because of the font size) even if the page is displayed from a mobile or desktop browser.
And, there are some options provided for a fine-tune including the ability to set “level of scaling” and mentioning min-max sizes.