Originally devised to enhance web pages in Netscape 2.0, JavaScript is now faced with being a single-threaded language in a multimedia, multitasking, multicore world. Yet JavaScript has not only persevered since 1995, it’s thrived. One after the other, potential rivals in the browser—Flash, Silverlight, and Java applets, to name a few—have come and (more or less) gone. Meanwhile, when a programmer named Ryan Dahl wanted to build a new framework for event-driven servers, he searched the far reaches of computer science for a language that was both dynamic and single-threaded before realizing that the answer was right in front of him. And so, Node.js was born, and JavaScript became a force to be reckoned with in the server world. How did this happen? As recently as 2001, Paul Graham wrote the following in his essay “The Other Road Ahead”: I would not even use JavaScript, if I were you... Most of the JavaScript I see on the Web isn’t necessary, and much of it breaks. Today, Graham is the lead partner at Y Combinator, the investment group behind Dropbox, Heroku, and hundreds of other start-ups—nearly all of which use JavaScript. As he put it in a revised version of the essay, “JavaScript now works.” When did JavaScript become a respectable language? Some say the turning point was Gmail (2004), which showed the world that with a heavy dose of Ajax you could run a first-class email client in the browser. Others say that it was jQuery (2006), which abstracted the rival browser APIs of the time to create a de facto standard. (As of 2011, 48 percent of the top 17,000 websites use jQuery.)