Bootstrap, from Twitter website in 2011
Bootstrap 1
2011 August 19th
Web developers Mark Otto and Jacob Thornton of Twitter began creating the CSS framework Bootstrap in mid-2011. The framework was originally developed to help maintain the HTML/CSS and JavaScript code consistency in Twitter applications. In August 2011, Bootstrap 1 was released as an open source tool and is currently one of the most popular CSS frameworks among web designers. In January 2012, Bootstrap 2 was released, supporting a responsive web layout.