GTN javascript

var computer = Math.random () * 3;
computer = Math.floor (computer);
computer = computer + 1;

function calculate (player)
{
    if (computer > player)
    {
         document.getElementById ("message").innerHTML = "my number is higher";
    }

    if (computer < player)
    {
         document.getElementById ("message").innerHTML = "my number is lower";
    }

    if (computer == player)
    {
         document.getElementById ("message").innerHTML = "you got it";
    }

}