Build an ajax code

Job ID: 32652083

Budget: $30 – $250 USD

Hi,
I would like to have an ajax function where does the following. First, I should have a plus and minus buttons where it duplicates rows in an unlimited number. Where the plus button adds a row and the minus one deduct a row.
Second, it sends a request to a PHP file where it searches for a product in the DB and returns the results in a select menu.
Third and most importantly, when PHP returns a response it should be reflected or echoed in the same select menu where I am typing NOT in any other input.
The system is too similar to the invoice systems where someone can search by barcode and if it exists it add it to the rest of items and so on.
an example of what exactly I want can be seen in this video:
https://youtu.be/TXkb2z5Ohf8?t=214
Related categories: PHP JavaScript AJAX MySQL jQuery / Prototype