portion of browser software that reads and executes javascript
JavaScript engine A JavaScript engine is a program or interpreter which executes JavaScript code. A JavaScript engine may be a traditional interpreter, or it may utilize just-in-time compilation to bytecode in some manner.[1] Although there are several uses for a JavaScript engine, it is most commonly used in Web browsers.[2][3][unreliable source?]
HTML Hypertext Markup Language (HTML) is the standard markup language for creating web pages and web applications. With Cascading Style Sheets (CSS) and JavaScript, it forms a triad of cornerstone technologies for the World Wide Web.[3] Web browsers receive HTML documents from a web server or from local storage and render them into multimedia web pages. HTML describes the structure of a web page semantically and originally included cues for the appearance of the document.