Javascript, JQuery, CSS

Javascript 

• Program behavior of web pages, web browser.
• Interpreter language (no need compile). [C# is Compiled Language]
• Case Sensitive
• Use Client side processor to execute.
• Faster, not require to process in the web server and sent back with server bandwidth. 
• Reduce Load on servers.
• Disadvantage :
• Security issue, the java script can exploit by user.
• Many version, different version may have different result. and also different browser too.

JQuery - Make it easier to use Javascript on your website

CSS 

• Describe how HTML element should display.
• Development faster, Low maintenance, no need change in every page.
• Disadvantage : 
• Fragmentation, different dimensions with each browser and also device (PC and mobile)

• select all p elements inside a div element? div p
• select elements with class name "test"? .test
• select an element with id "demo"?  #demo
• border-width:10px 1px 5px 20px; (Top, Right , Bottom, Left)