How to Create an Instant Image Preview in HTML with One Line of JavaScript

Sometimes you don't need a heavy library or a 50-line script just to show a preview of an image before uploading. In this tutorial, we will show you how to achieve a professional Image Preview feature using just one line of JavaScript code.

A high-quality preview of HTML image upload with instant JavaScript preview feature by FAMOUSCODE

Live Interactive Preview

Upload an image to see it appear instantly below.

The Complete Source Code

Copy the code below and paste it into your HTML file to get started immediately.

HTML5 STRUCTURE

<!DOCTYPE html>
<html lang="en">
<head>
    <title>Image Preview - FamousCode</title>
</head>
<body>

    <div>
        <!-- Image tag where preview will be shown -->
        <img id="output" width="200px" />
        
        <!-- The Magic Line -->
        <input type="file" accept="image/*" 
               onchange="document.getElementById('output').src = window.URL.createObjectURL(this.files[0])">
    </div>

</body>
</html>

Note: We use URL.createObjectURL() which creates a temporary URL for the selected file, allowing it to be displayed in the <img> tag instantly.

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