var x = document.getElementById("table").rows.length;
var y = document.getElementById("table").rows[0].cells.length;

for(var i = 1;i < x;i++) {
	var total = 0;
  for(var j = 2;j < y;j++) {
  	total += parseInt(document.getElementById("table").rows[i].cells[j].innerHTML);
  }
  document.getElementById("table").rows[i].cells[7].innerHTML = total;
}