Untitled

<!DOCTYPE html>
<html>
<head>
  <title>GRID!</title>
  <script src="jquery.min.js"></script>
  <style>
    body {
    }

    form input {
      width: 23px;
      float: right;
    }

    form label {
      height: 25px;
      clear: right;
      position: relative;
      width: 150px;
      display: block;
    }

    #grid {
      border: 1px solid black;
      position: relative;
    }

    #grid:before {
      content: "";
      border-top: 1px solid rgba(0, 0, 0, 0.2);
      height: 1px;
      width: 100%;
      left: 0;
      top: 50%;
      position: absolute;
    }

    #grid:after {
      content: "";
      border-left: 1px solid rgba(0, 0, 0, 0.2);
      width: 1px;
      height: 100%;
      top: 0;
      left: 50%;
      position: absolute;
    }

    .pixel {
      float: left;
      background: white;
      border: 1px solid #eee;
      border-left: 0;
      border-top: 0;
      z-index: 1;
    }

    .origin-x {
      border-right: 1px solid black;
      z-index: 10;
    }

    .origin-y {
      border-bottom: 1px solid black;
      z-index: 10;
    }
  </style>
</head>
<body>
  <div id="grid">
  </div>
  <script>
    // how many blocks in the x and y directions... so 10 is -10,10 / -10,10 (121 blocks)
    var gridSize = 25;

    // how big is each "pixel" - they are square, so this is width and height
    var pixelSize = 10;

    $(function () {
      // draw the grid
      var x,y;
      for (y = gridSize; y >= -gridSize; y--) {
        for (x = -gridSize; x <= gridSize; x++) {
          var id = pixelId(x, y)
          $("<div class='pixel' id='" + id + "'>").appendTo("#grid");
        }
      }

      var gridPx = ((gridSize * 2) + 1) * (pixelSize + 1);
      $("#grid").css({"width": gridPx + "px", "height": gridPx + "px"});
      $(".pixel").css({"width": pixelSize + "px", "height": pixelSize + "px"});

      function pixelId(x, y, append) {
        if (append === undefined) { append = ""; }
        return append + "pixel_" + x + "_" + y;
      }

      function setPixel(x, y, color) {
        $(pixelId(x, y, "#")).css("backgroundColor", color);
      }

      function getPixel(x, y) {
        return $(pixelId(x, y, "#")).css("backgroundColor");
      }

      $(".pixel").click(function () {
        var id = $(this).attr("id");
        var xy = id.split("_");
        var color = getPixel(xy[1], xy[2]);
        setPixel(xy[1], xy[2], (getPixel(xy[1], xy[2]) == "rgb(255, 255, 255)") ? "black" : "white")
      });
    });
  </script>
</body>
</html>