JSFiddle - React, Tailwind, and code Playground

HTML

<p id="demo"></p>

JavaScript

function myfunction(p1,p2)
{
    // valores inteiros  
    return parseInt(p1) * parseInt(p2); // ou
    //valores nĂşmericos com virgulas
    //return parseFloat(p1) * parseFloat(p2); 
}
document.getElementById("demo").innerHTML = myfunction(300,300);