getElementById

-Is an essential method commonly used in javascript in the browser to retrieve a particular element node in an html or xml document by its id.

Element-Is a reference to an element object or null an element with the specified id is not in the document.

Id is case-sensitive string representing the unique id of the element being sought.

innerHTML

-Is a document object model (DOM) nodels property that gets` or sets the innerHTML element.

-It is used to change or read from a page.