Sunday 21 July 2013

HTML, JavaScript, JQuery - Notes from different books


HTML lets people read text, look at pictures, and click links to move to other web pages with more text and pictures.

JavaScript lets a web page react intelligently. You can make elements appear, disappear, or move around a web page.

JavaScript lets web pages respond to visitors.

jQuery is a powerful JavaScript library that can enhance your websites.

Actually, HTML5 does add some smarts to HTML, you still need JavaScript to build the best.

Ajax is a method for using JavaScript to talk to a server, retrieve information from the server, and update the web page without the need to load a new web page.

In truth, JavaScript can also be a server-side programming language.

Learning a programming language is a lot like learning another language. You need to learn new words, new punctuation, and understand how to put them together so you can communicate successfully.

Translate your ideas into programming code
Task: Display a welcome message using the name of the person viewing a web page
Sub-task:1. Ask the visitor’s name.
Sub-task:2. Get the visitor’s response.
Sub-task:3. Print (that is, display) the message on the web page.

Web browsers are built to understand HTML and CSS.

Part of the web browser that understands HTML and CSS is called the layout or rendering engine.

Most browsers also have something called a JavaScript interpreter, part of the browser that understands JavaScript and can execute the steps of a JavaScript program.


Web browser is usually expecting HTML, you must specifically tell the browser when JavaScript is coming by using the <script> tag.
The <script> tag is regular HTML. Web browser hands it off to the JavaScript interpreter.When web browser encounters the </script> tag, it knows it’s reached the end of the JavaScript program and can get back to its normal duties.

Most web browsers are set up to silently ignore JavaScript errors!