JS Window Object is the global object in JavaScript. For a web browser, window object tell information about current browser window. Window Object is also the global object of browser environment.

window object is available in browser environment only. In other environment's, there is no window object. For exp, in Node JS, global is used instead of window object.

We can also use globalThis, a common object in modern JS for both frontend and backend.

All global variables and functions are windows properties and methods. See Example

    var x="hello js";
    var y=function(){ return "hi"};
    window.x;          // return "hello js"
    window.y();        // return "hi"

But Block scope const and let are not windows properties and methods.

    let x="hello js";
    let y=function(){ return "hi"};
    const pi=Math.PI;
    window.x;            // return undefined
    window.y;            // return window.y is not a function 
    window.pi            // return undefined 

Window Properties

Some common properties of Window Object.

Window Properties
Property Details Use
innerWidth width of window
innerHeight height of window
devicePixelRatio ratio of physical resolution by actual resolution

Window Methods

JS Window Methods or build in functions.

Window Methods
Method Use Open a new browser window. For exp"print.html","_blank","width=400,height=500,top=100,left=300,resizable=yes")
window.close() Close browser window opened by method. For exp
window.print() Print current browser window. Exp
window.resizeTo() resize browser to parameter inside. For exp window.resizeTo(600,400) will resize window to 600 by 400.
window.moveTo move window to left top corner of screen

Get all window Properties and methods

To get all windows properties and methods for current browser, we can use for in loop on window object. Most of the properties of windows objects are same on all browsers, but some may not exists on another browser. The reason is different browser engine.

for( let i in window){
    console.log(i, window[i]);

Output of loop in table

S No Property Value