JSFiddle - React, Tailwind, and code Playground

HTML

<input id="global" type="number" min="1" value="6">

JavaScript

let global = 6;

window.onload = function(){
    document.getElementById("global").onchange = function(){
        global = this.value;
        testing(7);
    }
}

function testing(param){
	mod(param, global);
}

function mod(a, b){
    let result = ((a%b)+b)%b;
    console.log("mod of ", a, " and ", b, " is:", result);
    return result;
}