I need help for selected option(option database and are data from the same table)

I’m looking for a way to prevent cross-site-scripting from happening in my Laravel app, but I don’t know how to test if the latter code works, how can I run tests?

I want to changes my main table quantity value when model quantity value changes for Laravel. I am trying to correct it but when model quantity changes, main table quantity not changing.

I want, when i will access my POS website via my phone, then i can scan barcode by phone camera.
Already i try quaggajs and html5-qrcode but sometimes they are give me wrong answer and it’s very slow.
Can you give me a solution to do it?