Running javascript in php foreach

Hello

Firstly, this is the full pastebin code of my admin page because i failed adding full code here correctly: https://pastebin.com/tQAaQjYC

and the screenshot of the slide manager page:
https://img36.imageshack.us/img36/4830/slidemanager.jpg

Well, I have a Slide Manager as an admin menu page in WordPress. When i click “Add new slide” button, as you see in the screenshot above, it adds a new “slide field” in which that dropdown list shows all titles of posts. (Ignore other parts as they work as expected)

What i would like to do is, when i choose a post title, the text box which is next to dropdown to be populated automatically by the post’s url adress. I want it to be worked for every “slide field” added via “Add new slide” button.

I actually made it work that way outside the foreach:

[Code moderated as per the Forum Rules. Please use the pastebin]

Each slide field shows the dropdown and text box properly as you see in screenshot BUT none of them work.

I tried to add brackets but it didn’t work either:

<select name="link[]" onChange="onChange(this.value);">

I guess it’s the javascript code that should be edited or entirely changed but i have no idea how to do it.

I would be grateful for any help. Thanks in advance.