HTMLify

const hex= [0,1,2,3,4,5,6,7,8,9, "A" ,"B" ,"C","D","E","F"];

const btn= document.getElementById("btn");
const color=document.querySelector(".bg");

btn.addEventListener('click', ()=>{
    let hexColor ='#';

    for(let i=0;i<6;i++)
    {
        hexColor += hex[randomNo()];
    }

    color.textContent = hexColor;
    document.body.style.backgroundColor=hexColor;
})

function randomNo()
{
    return Math.floor(Math.random() * hex.length);
}