May 30, 2016 5:54 am

How to show Image before upload JavaScript & HTML5 FileReader()

Show image before upload is a requirement of every web application to give good user experience. We published a tutorial that dose’t work in all browsers so, now I am going to give you this tutorial it will work on every browser which support HTML5  File API and JavaScript check compatibility of API here. I hope you like this tutorial as all other tutorials.Image before upload JavaScript & HTML5 FileReader

First of all we need to know what is FileReader?

FileReader is an API of HTML5 used to interact local files. Example of its capabilities, the FileReader API could be used to create a thumbnail preview of images as they’re being sent to the server. You could use client-side logic to verify an upload’s file type matches its file extension or restrict the size of an upload etc.

Browser compatibility for filereader api

Let’s start with HTML for single file show thumbnail

That above code show you a file uploader you can select 1 file at a time.

JavaScript code to show image thumbnails

That above JavaScript calls on change event of file element. This example can upload 1 file at a time for multiple files you can add a for loop as below.

This will show you multiple files thumbnails after selection. for complete source code Download it and enjoy.

If you face any issue in its configuration please feel free to comment we love to help you.

Author Huzoor Bux

I am Huzoor Bux from Karachi (Pakistan). I have been working as a PHP Developer from last 5+ years, and its my passion to learn new things and implement them as a practice. Basically I am a PHP developer but now days exploring more in HTML5, CSS and jQuery libraries.

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  • Vovan

    Great tutorial thanks !
    Also will be great if you can show how to delete preview images 1 by 1 , thanks in advance!

  • I’ve tried your code and uploaded to my web site. It displays the single image input and multi image user input prompts and I can browse and select images from my local C drive on either option but then nothing happens. No image is displayed. It just sits there and no error messages. I tried using IE and Chrome but same result.

  • Kiran Bisht

    function handleFileSelect(evt) this function is not called anywhere? Where can I find the functionality of this function.?