draw_signature_paint

function draw_signature(e)
{
  //document.getElementById("content") or $("#content")[0] it's basically the same
  var objContent = $("#content")[0];
  var xClicked   = e.pageX - objContent.offsetLeft;
  var yClicked   = e.pageY - objContent.offsetTop;
  var ctx        = objContent.getContext("2d");

  ctx.beginPath();
  ctx.moveTo(xClicked, yClicked);
  ctx.lineTo(xClicked + 1, yClicked + 1);
  ctx.stroke();
}