This is a summarized form of the JavaScript Tutorial.

For reference JavaScript specifications can be found here .

• JavaScript is the most popular scripting language on the internet and works in all major browsers.
• It is a lightweight, interpreted language that is embedded into webpages to add interactivity.
• JavaScript can read and write HTML page elements, react to events, validate data, create cookies.
• JavaScript was invented by Brendan Eich of Netscape but is now known officially as ECMAScript (current version is ECMA-262).
• A simple “Hello World” example

  <script type="text/javascript">
  <!--
  document.write("Hello World!");
  //-->
  </script> 

• JavaScript code may be located
  • In the head - executed when called
  • In the body - executed while loading
  • In an external file called from either the head or the body e.g. <script src=“abc.js”></script>