JSFiddle - React, Tailwind, and code Playground

HTML

<div id="output">output log</div>

JavaScript

var myfunc = false;

if(document.addEventListener)
{
    myfunc = function() {
        var sum = 0; for(var i=0, e=arguments.length; i<e; i++) {
            sum += (typeof arguments[i] === 'number' ?  arguments[i] : 0); 
        }
        return sum;
    };
}

if(myfunc !== false) {
    document.querySelector("#output").innerHTML = myfunc(1,2,3,4,5,6);
}