Javascript Hide Codes

For hiding JavaScript codes from old browsers:

Add “<!–” without the quotes in the code just after the <script> tag.

Add “//–>” without the quotes in the code just before the <script> tag.

Old browsers will now treat this JavaScript code as a long HTML comment. While, a browser that supports JavaScript, will take the “<!–” and “//–>” as one-line comments.

Javascript Screen Objects

Screen objects are used to read the information from the client’s screen. The properties of screen objects are

  • AvalHeight: Gives the height of client’s screen Gives the width of client’s screen.
  • ColorDepth: Gives the bit depth of images on the client’s screen
  • Height: Gives the total height of the client’s screen, including the taskbar
  • Width: Gives the total width of the client’s screen, including the taskbar

Javascript Functional Components

The different functional components in JavaScript are-

First-class functions: Functions in JavaScript are utilized as first class objects. This usually means that these functions can be passed as arguments to other functions, returned as values from other functions, assigned to variables or can also be stored in data structures.

Nested functions: The functions, which are defined inside other functions, are called Nested functions. They are called ‘everytime’ the main function is invoked.

Javascript Deferred Scripts

By default, the parsing of the HTML code, during page loading, is paused until the script has not stopped executing. It means, if the server is slow or the script is particularly heavy, then the webpage is displayed with a delay. While using Deferred, scripts delays execution of the script till the time HTML parser is running. This reduces the loading time of web pages and they get displayed faster.

Magento Code Pool

codePool is a tag which you have to specify when registering new module in app/etc/modules/Company_Module.xml
There are 3 codePools in Magento: core, community and local, which are resided at app/code/ directory.
Core codePool is used by Magento core team, Community is generally used by 3rd party extensions and Local codePool should be used for in-hour module development and overriding of core and community modules for custom requirement.
So in short, codePool helps Magento to locate module inside app/code/ for processing.