How to Create a QR Code Reader for Your Mobile Website

The barcode and QR code have modernized our shopping and searching experience. Customers carrying smartphones can now pick up a product anywhere in the world, scan its barcode or its QR code using one of the many free phone apps and find out its lowest price as well as where it can be bought.

Companies like Walmart and Amazon have embraced this technique to draw customers to their online and offline stores using their phone app. Other companies like Fedex and UPS allow customers to scan the codes on packages using a phone app, instead of needing to manually type in long lists of characters.
If the users of your mobile website have a need to type in long codes like activation codes or they like to look up specific products on your website based on a model number printed in a magazine or advertisement, then you too can take advantage of QR codes to eliminate the frustration of tiny keyboards and spare them the need to double check for errors.
QR Code Scanning with your Mobile Website
You don’t need a native phone app to scan QR codes β€”it’s quite simple to create your own QR code reader. Your website running on a smartphone equipped with a camera and running a little JavaScript can do the same trick.
Here is a demo of a text field with an in-built QR button. In addition to being able to type text into the field, users can also click a button to activate the camera.

Browser Requirements:
Your users need to be on an iPhone running iOS 6 or higher or an Android phone running Android 3.0 or higher. Other devices have not been tested.

See the Pen Bare QR reader demo by SitePoint (@SitePoint) on CodePen.

If you are on a supported device, go ahead and click it. Depending on your phone, it will either launch the camera immediately or ask you whether to open the camera or browse your photo library. On unsupported devices, the browser will open up a regular file explorer window.
If you don’t have a QR code handy to scan, here is one that shows the first 8 digits of Pi.

Creating the QR Code Reader
The magic starts with the file upload element. We spruce it up with an accept attribute which tells the browser that we only want images and we give it a capture attribute which means we want the input to be captured now, as opposed to uploading an old picture from the phone’s memory.

Link: https://www.sitepoint.com/create-qr-code-reader-mobile-website/