Understand how DOM is build — — When something in the DOM is change then it is very fast to paint. But the changed element and it’s children’s has to go through layout stage and then the changeshas to be re-painted which are slow. …

What is cross browser testing? Cross browser testing is a practice that a web site or web app you created can work on acceptable number of web browsers. As a web developer, you have to ensure that your project will not only work for you also can work for your all…

Number.isNaN — — Number.isNaN() Method check that the value passed is NaN and it’s type is Number. Syntex:- Number.isNaN(value) It return true if the given value is NaN and it’s type is Number. Otherwise it return false. It is different from global isNaN() Method. Example:- function typeOfNaN(a) { if (Number.isNaN(a)) { return true…