Build a before-and-after image tool with HTML, CSS, and JavaScript
A picture doesn't always tell the whole story. But two pictures can make a difference. Imagine a garden where a large tree has been cut down. The owner would like to compare the area before and after the work. How much light has come in? What does the garden look like without the large crown? And which parts of the area have been changed? This is a good example of a small web function that can be useful in…
Building a "before-and-after" image comparison tool using HTML, CSS, and JavaScript offers a practical example of how simple web functions can be beneficial in various projects. The tool allows users to select two images from their own computers and view them side by side in a browser. No external libraries are required, and no backend is involved, meaning the demo does not upload images to a server.
The project files consist of three main components: index.html, style.css, and script.js. These files can be opened in any preferred code editor without the need for a framework. The HTML structure begins with an introduction header, instructions informing users that images are not sent to a server, and a section for uploading files. Two file input fields are provided for the "before" and "after" images, each with a clear label identifying the purpose of the respective image.
A responsive layout is achieved by arranging the images side by side on larger screens and stacked underneath on mobile devices. The CSS file ensures consistent styling across different devices, with specific styles for the container, headers, and grid layouts. JavaScript is used to handle the image selection and display functionality, enabling users to reset the comparison by removing the displayed images.
The tool also ensures accessibility by allowing keyboard navigation and includes a live status message for users. Importantly, it is designed with privacy in mind, not persisting any images permanently, which is crucial for protecting personal information.
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