This post takes a look at what page visibility is, how you can use the Page Visibility API in your applications, and describes pitfalls to avoid if you build features around this functionality....hidden Boolean property: js console.log(document.visibilityState);...checking the visibility manually: js document.addEventListener("visibilitychange"...
At this point, you should have a useful idea of the basics of graphics programming using Canvas and WebGL and what you can do with these APIs, as well as a good idea of where to go for further information. Have fun!...js" "style.css" Open "index.html"..."script.js" and add the following lines of JavaScript: js const...
In this article, we've gone through the main tools available in JavaScript for writing object-oriented programs. We haven't covered everything here, but this should be enough to get you started. Our article on Classes is a good place to learn more....Person from the previous article: js class Person { name; constructor(name)...new Person instance like this: js const giles = new Person("Giles");...
The Prioritized Task Scheduling API provides a standardized way to prioritize all tasks belonging to an application, whether they are defined in a website developer's code or in third-party libraries and frameworks.... js async function slowTask() { firstHalfOfWork();...or have its priority changed. js const promise = scheduler.postTask(myTask);...
The intersection() method of Set instances takes a set and returns a new set containing elements in both this set and the given set.... Syntax js intersection(other) Parameters...numbers that are perfect squares. js const odds = new Set([1, 3, 5...
Learn about the ContactsManager interface, including its methods, code examples, specifications, and browser compatibility.... js const supported = "contacts"...check for supported properties. js async function checkProperties()...
Learn about the HTMLElement.blur() method, including its syntax, code examples, specifications, and browser compatibility.... Syntax js blur() Parameters None. Return...gain focus</button> JavaScript js function focusInput() { const...
A FinalizationRegistry object lets you request a callback when a value is garbage-collected....registry passing in the callback: js const registry = new Finaliz...value and a held value for it: js registry.register(target, "some...
The JavaScript exception "numbers out of order in {} quantifier" occurs when a quantifier in a regular expression uses the {n,m} syntax but m is less than n....Invalid examples js /1{2,1}/; Valid examples js /1{1,2}/; See also...