Browser engine is an application which is embedded in every web browser . Its purpose is to help browsers render web pages properly.Initially Web sites were built using HTML and CSS . To render such Web Pages Layout engines or rendering engines were used .The layout of a web page is typically specified by Cascading Style Sheets (CSS). Each style sheet is a series of rules which the browser engine interprets. For example, some rules specify typography details, such as font, colour, and text size. Some browser engines may begin rendering before receiving the contents of a Web page from the server. It results in partial loading of elements , filling of colours in the web page gradually. With the advent of Javascript (initially called Livescript) in 1990’s , rendering the Web Pages for Browser engines was becoming a difficult task. To tackle this problem Javascript engines were introduced (as one of the components of the browser engine ) . e.g., One notable Javascript engine is V8 developed by Google to interpret and render Javascript code in browsers . V8 was later modified by Ryan Dahl and transformed into a development environment called Node.js in which we can create webapps using frameworks like React, Angular etc.

Some notable browser engines :

Depending on browser we’ve different engines , e.g., Webkit in Safari , Blink in Google Chrome , Gecko in Mozilla Firefox , Trident and EdgeHTML for Microsoft’s Internet Explorer and Microsoft Edge respectively.