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JavaScript One Solution

Julieta Dalla Pozza
Julieta Dalla Pozza
4,337 Points
Posted by Julieta Dalla Pozza
Julieta Dalla Pozza
4,337 Points

Select elements by id or class

Hi, i am a lil confused here. Sometimes to get an element by id you need to put # or if is a class you need a dot but sometimes you don't. Don't get it much when is necessary and when is no?

2 Answers

Steven Parker
Steven Parker
231,275 Points
Steven Parker
Steven Parker
231,275 Points

Functions that are simple and only take one kind of argument (like getElementById and getElementsByClassName) use only the name.

But querySelector (and querySelectorAll) takes a complex argument which works like a selector in CSS. So it uses the CSS syntax to indicate what kind of thing it is looking for where an ID is preceded by "#", and a class by ".".

Tony Idehen
Tony Idehen
8,060 Points
Tony Idehen
Tony Idehen
8,060 Points

The document.querySelector(selectors) and document.querySelectorAll(selectors) uses the CSS selectors, so the selectors must be written as represented or be written in CSS(i.e # before the Id name, .(dot) before the class name , h2 or img ). My understanding, the getElementById(idname) and getElementsByClassName(classname) are specifically asking for elements with id or classname. Hence you give only the names as written in html. You don't need to add the dot(.) or # before the names.