Скачать или смотреть How to Highlight Text on Scroll with JavaScript

Learn how to highlight text when scrolling using JavaScript. This guide breaks down common mistakes and provides code snippets for easy implementation. Perfect for beginners!
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How to Highlight Text on Scroll with JavaScript: A Step-by-Step Guide

Have you ever wanted to add a touch of interactivity to your web pages by highlighting text when the page scrolls? If you're just starting your web development journey, this can seem like a daunting task. But fear not! In this post, we’ll explore how to accomplish this using JavaScript, along with some insights to troubleshoot common issues.

The Problem: Highlighting Text on Scroll

Many budding developers face challenges when trying to implement features like text highlighting on scroll. A common approach is using JavaScript's Intersection Observer API. However, even if your code looks correct, subtle details can lead to unexpected behavior.

Example Scenario

Let's say you have a paragraph of text, and you want specific keywords or phrases to shine as users scroll down. Here’s how you might think to implement it:

Write HTML that includes <mark> elements for the text you want to highlight.

Create CSS to define the appearance of the highlights.

Use JavaScript to observe when these elements come into view during scrolling.

The Solution

Step 1: HTML Structure

Your HTML should have text wrapped in <mark> tags. Here’s a simple example:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: CSS Styling

You might make a few mistakes here. It's important to properly declare your CSS properties. Here's how your CSS should look:

[[See Video to Reveal this Text or Code Snippet]]

Step 3: JavaScript Logic

This is where you use the Intersection Observer to listen for scrolling events. Here’s an essential snippet for achieving the highlight effect:

[[See Video to Reveal this Text or Code Snippet]]

Common Mistakes and Corrections

CSS Errors: One common error is missing commas in the linear-gradient property. Ensure your gradients are declared correctly, such as linear-gradient(var(--color1), var(--color2)).

Targeting the Correct Elements: Make sure you are styling the <mark> elements directly, not a class like .mark unless that class is applied to those elements.

Advanced Techniques

If you’re looking for more refined control over animations and events, consider using the GSAP ScrollTrigger plugin. This powerful tool makes it easier to manage complex scroll-related animations without having to manipulate the CSS and Intersection Observer directly.

Conclusion

Highlighting text on a scroll event can enhance user experience significantly. By following the steps outlined above, you should be able to implement this feature successfully. Remember to double-check your CSS and HTML for any subtle mistakes that could prevent the highlight effect from functioning as expected. Happy coding!