JavaScript for beginners / PDF

 JavaScript for beginners / PDF

Sample of the pdf document 

Introduction to JavaScript

• NOT Java
– JavaScript was developed by Netscape
– Java was developed by Sun

• Designed to ‘plug a gap’ in the techniques available for creating web-pages
– Client-side dynamic content
• Interpreted


JavaScript vs. Java
• JavaScript is becoming what Java was originally intended to be

– Java Applets are meant to be lightweight downloadable programs run within the browser for cross platform compatibility
– Java = Bloated
– JavaScript is actually lightweight and accomplish most of what Applets do with a fraction of the resources


What is it used for today?
• Handling User Interaction
– Doing small calculations
– Checking for accuracy and appropriateness of data entry from forms
– Doing small calculations/manipulations of forms input data
– Search a small databased embedded in the downloaded page
– Save data as cookie so it is there upon visiting the page

• Generating Dynamic HTML documents

• Examples
– Bookmarklets
– Google Maps
– Google Suggest


JavaScript Syntax - Variables and Literals

• Declaration
– Explicit: var i = 12; // no ‘var’ in declaration
– Implicit: i = 12;
• Variable Scope
– Global
• Declared outside functions
• Any variable implicitly defined
– Local
• Explicit declarations inside functions

  JavaScript for beginners / PDF