Understanding Why 100vh Produces Horizontal and Vertical Scrollbars on Web Pages
Introduction
When developing web pages, you might encounter an issue where the use of 100vh results in both horizontal and vertical scrollbars. This can be quite perplexing, especially when the content doesn't extend beyond the viewport height and width. This article aims to explore the reasons behind this issue and provide practical solutions to mitigate it.
Key Concepts
What is 100vh?
100vh is a CSS unit that represents 100% of the viewport height. It is often used to make an element fill the entire viewport or to create flexible layout structures. However, misusing it can lead to unexpected scrollbar behavior.
The Problem Explained
The primary issue arises from two main causes: global width and height, and overflow, flexbox, and shrink properties. Let's break down each of these to understand the problem more clearly.
Global Width and Height
When setting the width and height properties on the global level (e.g., on the body or html element), they can sometimes interfere with the viewport's measurement. Setting the body or html to a fixed width or height can override the default viewport height, leading to unnecessary scrollbars.
Overflow and Flex Shrink
Overflow properties like overflow-x and overflow-y are used to control how content is clipped when it overflows the container. By default, if the content is not fully contained within the viewport, horizontal scrollbars appear. Similarly, the flex-shrink property can cause items in a flex container to shrink beyond the viewport, leading to vertical scrollbars if the content exceeds the viewport height.
Practical Solutions
1. Properly Define Viewport Height
Ensure that the 100vh unit is used correctly by setting appropriate styles on the HTML and body elements. For instance, setting html, body { height: 100%; } can help.
2. Use Flexbox and Grid Wisely
When using flexbox or grid layouts, ensure that there are no unwanted overflow properties that could cause scrollbars. Use the overflow-x: hidden and overflow-y: hidden properties to explicitly remove scrollbars and maintain a seamless viewport experience.
3. Flex Shrink Adjustments
Adjust the flex-shrink property of elements within a flex container to prevent them from shrinking beyond the viewport. This can be done by setting flex-shrink: 0 for elements that should not shrink.
4. Inspect and Adjust Other Dimensions
Check if any other elements on the page are causing the issue by inheriting styles or overwriting viewport dimensions. Use browser development tools to analyze the computed styles and identify potential conflicts.
Conclusion
Understanding and resolving the issue with 100vh producing horizontal and vertical scrollbars is crucial for optimizing web performance and user experience. By addressing global width and height settings, overflow properties, and flexbox behavior, developers can create seamless and responsive web designs. Always test your pages thoroughly to ensure that all scrollbars are functional only when needed, providing a cleaner and more user-friendly browsing experience.