FUNDAMENTALS

• Shortest JS program is nothing but an Empty js file.

• But there is a lot of things done by JS Engine when it is executed.

• It creates GEC and also it creates "window" and this variable.

• Window is a big global object that has a lot of functions and variables.

• We can access these functions anywhere inside our JS program, and this is provided by our JS Engine itself.

• this variable points to window.

• Whenever a GEC is created, a this is created along with it. Here the Global object provided by the browser engine is window, so this points to window.

GLOBAL SPACE

• It is anything that is not inside any function. In global space variables and functions can be present.

• Whenever in a JS file, we create a global variable or a function, it gets attached with the window object and can be accessed through it.

// code example 1
a=10;
console.log(window.a);
console.log(a);
console.log(this.a);

Outputs:

10

10

10