CodePrimer
Search a living directory of web syntax. Pick a problem, copy a working sample, then adapt it.
JavaScript
Beginner
document.getElementById
How do I select one element by id?
JavaScript
Beginner
document.querySelector
How do I select with a CSS selector?
JavaScript
Beginner
document.querySelectorAll
How do I select every matching element?
JavaScript
Beginner
addEventListener click
How do I make a button show an alert?
JavaScript
Beginner
Arrow function event listener
Can I use an arrow function for events?
JavaScript
Beginner
Live input event
How do I react as the user types?
JavaScript
Beginner
change event on select
How do I detect dropdown changes?
JavaScript
Beginner
innerHTML vs textContent
How do I change an element’s text?
JavaScript
Beginner
setAttribute and style
How do I change attributes and CSS from JS?
JavaScript
Beginner
classList toggle
How do I toggle a CSS class?
JavaScript
Beginner
createElement and appendChild
How do I add a new element with JS?
JavaScript
Beginner
Remove a DOM node
How do I delete an element?
JavaScript
Beginner
Read input/select/textarea values
How do I read form field values in JS?
JavaScript
Beginner
Read data-* with dataset
How do I read data-price in JavaScript?
JavaScript
Beginner
mouseover tooltip style
How do I run code on hover?
JavaScript
Beginner
Keyboard keydown shortcut
How do I listen for a key press?
HTML
Beginner
Custom data-* attributes
How do I store extra data on an element?
JavaScript
Beginner
Wait for DOMContentLoaded
Why is getElementById null?