How do i make a sleep function in JS? It dosent have to be the best way, just a way that i understand because i want to learn

Question

Why dosent this work? When i run call the function like this "sleep(2)" the entire website crashes. I know that is because the while loop never breaks but i dont get why i dosent.

function sleep(seconds)
{

    const d = new Date();
   var oldTime = d.getSeconds;
    while(true)
    {
        
        if((d.getSeconds - oldTime) ==  seconds)
        {
            break;
        }
    }
}