Introduction to css framework

The Internet industry has been developing for many years, the browser also from the earliest popular NS to the current FF3.IE7 and so on ...... front-end development engineer position is also born. In recent years in web development, there is a very hot word - "framework". YUI, JQuery, Prototype javascript frameworks in the development of the site, really become a front-end development engineers in the hands of the tool! Why? Why? Because the framework is to include tools, libraries, conventions, as well as trying to abstract from common tasks can be reused common module, so that designers and programmers to avoid duplication of development.