Skip to main content

WINDOW vs SCREEN vs DOCUMENT


WINDOW vs SCREEN vs DOCUMENT


        When JavaScript is executed inside the browser, the window object is the JavaScript Global object.  Screen and document are property of the window object.
          When an HTML document is loaded into a web browser, it becomes a document object. It is the root node of the HTML document. The document actually gets loaded inside the window object and has properties available to it like title, URL, cookie, etc.
          Screen is a small information object about physical screen dimensions. It can be used to display screen width, height, colour-depth, pixel-depth etc.

Comments

Post a Comment

Popular posts from this blog

NULL VS UNDEFINED

NULL VS UNDEFINED        Undefined means a variable has been declared but has not yet been assigned a value. On the other hand, null is an assignment value. It can be assigned to a variable as a representation of no value. Also, undefined and null both are two different data types: undefined is a type itself (undefined) null is an object. var a;//undefined var b = null; var c=5; var d = a+c // NaN var e = b+c  //5   If  I am trying to do any mathematical  operation with null and number it gives me some  number as output,  instead of null if i am doing it with undefined and number the result is NaN null !== 0;    undefined !==0;
Post a Comment
Read more

AUTH and CORS

   CORS 1. CORS is a mechanism that uses additional HTTP headers to tell browsers to give a web application running at one origin, access to selected resources from a different origin. A web application executes a cross-origin HTTP request when it requests a resource that has a different origin (domain, protocol, or port) from its own. 2. An example of a cross-origin request: the front-end JavaScript code served from https://domain-a.com uses XMLHttpRequest to make a request for https://domain-b.com/data.json. 3. For security reasons, browsers restrict cross-origin HTTP requests initiated from scripts. For example, XMLHttpRequest and the Fetch API follow the same-origin policy. This means that a web application using those APIs can only request resources from the same origin the application was loaded from unless the response from other origins includes the right CORS headers. 4. The CORS mechanism supports secure cross-origin requests and data transfers between bro...
Post a Comment
Read more

JAVASCRIPT OBJECT & ITS INTERNAL REPRESENTATION

OBJECT Objects are same in all programming languages i.e they represent real-world things that we want to represent inside our programs with characteristics/properties and methods. In JavaScript Objects are kind of String/Number   Index Array represented inside curly brackets Var obj = { 1: “NAME”, "Maths" :100 } KEY VALUE PAIR In the above example obj is an object with 2 properties with key as 1 and Maths and value as Name and 100 .Here the index are called as KEY.KEY :VALUE pair together called as entries Object literals are a comma-separated list of key-value pairs wrapped in curly braces. Object literal property values can be of any data type, including array literals, functions, nested object literals or primitive data type. Obj Values   in the above can be accessed via Dot notation i.e obj.1 ,obj.Maths   or via a square bracket notation i.e obj[1] ,obj[“Maths”] Object.assign() METHOD As we discussed earlier in JavaScript Objects are kind of...
Post a Comment
Read more