Q.Which JavaScript method is commonly used to find a single element on a page by its unique id so the script can change it?
(A) document.write()
(B) document.getElementById()
(C) alert()
(D) console.log()

This tests how JavaScript reaches into the page through the DOM to locate and modify an element. …

JavaScript changes a page through the DOM, first finding an element and then changing it.

(A) document.write() writes text into the document as it loads and can overwrite the whole page if used later — it does not select an element — incorrect.

(B) document.getElementById("id") returns the one element with that id so the script can read or change it (e.g. its innerHTML) — correct. …

Confusing output methods (alert, console.log, document.write) with element-selection methods. Only getEle …