YiXu Zhang

YiXu Zhang

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Building A Dynamic Header With Intersection Observer

In JavaScript, attaching an event listener to constantly fire a callback on scroll can be performance-intensive. But there is a better way with Intersection Observer.

The Intersection Observer API is a JavaScript API that enables us to observe an element and detect when it passes a specified point in a scrolling container — often (but not always) the viewport — triggering a callback function.

Intersection Observer can be considered more performant than listening for scroll events on the main thread, as it is asynchronous, and the callback will only fire when the element we’re observing meets the specified threshold, instead every time the scroll position is updated. In this article, we’ll walk through an example of how we can use Intersection Observer to build a fixed header component that changes when it intersects with different sections of the webpage.

#javascript #web-development #webdev

Building A Dynamic Header With Intersection Observer