JSFiddle - React, Tailwind, and code Playground

HTML

<input type="submit" id="plus1" value="+" style="font-weight:bold; width:50px; height:50px;" tabindex="-1">
<div id="testarea">testarea:</div>

JavaScript

var i = 1;
var loopthis=null;
$("#plus1").on('mousedown',function () {
    loopthis = setInterval(repeatingfunction, 100);
}).on('mouseup',function () {
    clearInterval(loopthis);
});

function repeatingfunction() {
    console.log("alerting");
    $("#testarea").text(i);
    i++;
}