Global_DOM_BOM

BOM (Browser Object Model)

• There is no standardization done
• It is represented by window object
• Javascript can talk to Browser using BOM
• It includes:
  • navigator
  • screen
  • location
  • history
  • document (DOM)

DOM (Document Object Model)

• It is part of BOM (window)
• It is represented by document
• It stores the the content of the page as tree data structure which can be manipulated by javascript

Global object

• In Browser environment window is global object
• In Nodejs environment global is global object

// Browser - create a global variable
window["myvar"] = value
 
// Nodejs - create a global variable
global["myvar"] = value

• The properties of global object can be accessed directly without mentioning global variable

window["myvar"] = 3;
console.log(window.myvar); // 3
console.log(myvar); // 3