change margin with javascript code example

Example 1: modify margin top javascript

window.onscroll = function() { document.getElementById('id').style.margin = '40px 0 0 0' }

Example 2: js add margin with variable

var players = document.getElementsByClassName('player');
for(var i = 0; i < players.length; i++)
    players[i].style.marginTop = playerPosition+"px";