Welcome to TypeScript. JavaScript Garden. Although JavaScript deals fine with the syntax of two matching curly braces for blocks, it does not support block scope; hence, all that is left in the language is function scope. function test() { // a scope for(var i = 0; i < 10; i++) { // not a scope // count } console.log(i); // 10} There are also no distinct namespaces in JavaScript, which means that everything gets defined in one globally shared namespace. Each time a variable is referenced, JavaScript will traverse upwards through all the scopes until it finds it. In the case that it reaches the global scope and still has not found the requested name, it will raise a ReferenceError.
The Bane of Global Variables // script Afoo = '42'; // script Bvar foo = '42' The above two scripts do not have the same effect. Again, that is not at all the same effect: not using var can have major implications. // global scopevar foo = 42;function test() { // local scope foo = 21;}test();foo; // 21 Local Variables var foo = 3; bar = 4;}test(10); Hoisting. Create a new Fiddle - jsFiddle - Online Editor for the Web (JavaScript, MooTools, jQuery, Prototype, YUI, Glow and Dojo, HTML, CSS) jQuery: The Write Less, Do More, JavaScript Library. Node.js. An example: Webserver This simple web server written in Node responds with "Hello World" for every request.
To run the server, put the code into a file example.js and execute it with the node program from the command line: % node example.js Server running at Here is an example of a simple TCP server which listens on port 1337 and echoes whatever you send it: var net = require('net'); var server = net.createServer(function (socket) { socket.write('Echo server\r\n'); socket.pipe(socket);}); server.listen(1337, '127.0.0.1'); Featured Node.js at Walmart Eran Hammer, Principal Architect at Walmart, talks about how they use Node.js as a way to reinvent legacy APIs to create modern front end experiences.