Trigger a jQuery function from another file in JS

How I can call/trigger a jQuery function (which is in another file) from JS. So basically this is the jQuery function (/js/animation.js).

$('#spin').click(function () {
    var tickets = Math.floor(Math.random() * 200) + 1;
    if(tickets < 51) {  
    var winner = 155;
    }
    else {
    var winner = 145;   
    }
    rouletteSpin(winner);
});

I know that its based on a codepen Roulette Animation. Now the problem is that it should not roll without going through an if statement. The statement should be a variable using Database info. That's the point. In my opinion you cant use PHP / select DB Info in jQuery so I decided to go into my index.php to trigger the jQuery function after the if statement in js went through. So let me show you my HTML Button + JS Function:

 onclick="openCase()

into the first HTML Button tag.

Now the JS Function:

    <script>    
    var credits = CodeToGet_MYSQL_DB_Info_here_written_in_php;


    function openCase() {
    if(credits > 10000) {
     spinIt();
    }
    else {
        alert('Something went wrong');
    }
    }

And changed the jQuery Function (in path /js/animation.js) to the following:

function spinIt () {
    var tickets = Math.floor(Math.random() * 200) + 1;
    if(tickets < 51) {  
    var winner = 155;
    }
    else {
    var winner = 145;   
    }
    rouletteSpin(winner);
});

That is not working. I already googled a lot so please don't flame me. Already used pretty much every method of this post:

calling Jquery function from javascript

Would be nice if someone can help me out!