Node.js Get Started

Nodejs Course

Installing Node.js

To install Node.js, you can use an installer or a binary package, from node.js website: Node JS Downloads.
- I downloaded the windows binary package, then I extracted the files from the .zip archive into a directory named "nodejs", in partition" E" (you can install it in any directory you want).

- The official Node.js website has installation instructions on various platforms (Windows, Linux, Unix, Mac OS X, etc.): Installing Node.js via package manager.

Simple Node.js server script

Once you have downloaded and installed Node.js on your computer, you have to write a .js script that will create and start the server.
- In Node.js you use modules to build your script. A module is the same as a JavaScript library, that are included with the require() function.

1. I have Node.js (V.8) installed in "E:/nodejs/" directory. For tests, I created in this directory a folder named "test".
2. Now, in the "test" folder (E:/nodejs/test/) I create a file named "server.js" (you can choose any file name), and added the following code (Click on the code to select it):

//include the http module
const http = require('http');

//define constant for port
const port =8080;

//sets the server
const server = http.createServer((req, res)=> {
  res.writeHead(200, {'Content-Type':'text/plain'});
  res.write('Hello to me.');
  res.end();
});

//pass the port to server to listen to
server.listen(port, ()=> {
  console.log('Server running at //localhost:'+ port +'/');
});

- The code tells the computer to write "Hello to me." if anyone (e.g. a web browser) access the computer on port 8080.

3. The Node.js server must be initiated in the "Command Line Interface" program of your computer.
- To open the command line interface on windows, press the Start button and write "cmd" in the search field.

4. In the command line interface window I navigate to the folder that contains the Node.js application (E:/nodejs/), then, to initiate the "server.js" script, I write: "node test/server.js", and hit Enter.
In the command line interface window, node.js displays: "Server running at //localhost:8080/".

- Now, the computer works as a server.

5. I open the browser, and I type in the address: http://localhost:8080
- Results:
• To close the Node.js server, press Ctrl+C in the command line interface window, or just close that cmd window.

<meta name="description" content="70-160 characters that describes the content of the page" />

#some_id {
  clear: both;
}

var divs = document.getElementsByTagName("div");
var nr_divs = divs.length;
alert(nr_divs);

$arr =[7, 8, "abc", 10);
$nri = count($arr);
echo $nri;        // 4