Edit in JSFiddle

var paper = Raphael(10,10,500,500);
paper.path("M 0 0 L 0 500");

for(var i = 0; i< 50; i++)
  {paper.path("M" +i*10 +"  20 L " + i*10 + " 500");
   }

for(var j = 0; j< 50; j++)
{
    paper.path("M 0 "+j*10+" L 500 "+j*10);

}