sketch,js on mobile devices

Question

I'm hoping someone smarter than me can help me with this. I'm trying to use sketch.js on my website Custom Kid Art.

It works great on every browser on my desktop, but on mobile devices, when you draw something, it disappears when you touch the screen again.

Here's the stetch.js code:

var __slice = Array.prototype.slice;
(function($) {
  var Sketch;
  $.fn.sketch = function() {
    var args, key, sketch;
    key = arguments[0], args = 2 <= arguments.length ? __slice.call(arguments, 1) : [];
    if (this.length > 1) {
      $.error('Sketch.js can only be called on one element at a time.');
    }
    sketch = this.data('sketch');
    if (typeof key === 'string' && sketch) {
      if (sketch[key]) {
        if (typeof sketch[key] === 'function') {
          return sketch[key].apply(sketch, args);
        } else if (args.length === 0) {
          return sketch[key];
        } else if (args.length === 1) {
          return sketch[key] = args[0];
        }
      } else {
        return $.error('Sketch.js did not recognize the given command.');
      }
    } else if (sketch) {
      return sketch;
    } else {
      this.data('sketch', new Sketch(this.get(0), key));
      return this;
    }
  };
  Sketch = (function() {
    function Sketch(el, opts) {
      this.el = el;
      this.canvas = $(el);
      this.context = el.getContext('2d');
      this.options = $.extend({
        toolLinks: true,
        defaultTool: 'marker',
        defaultColor: '#000000',
        defaultSize: 5
      }, opts);
      this.painting = false;
      this.color = this.options.defaultColor;
      this.size = this.options.defaultSize;
      this.tool = this.options.defaultTool;
      this.actions = [];
      this.action = [];
      this.canvas.bind('click mousedown mouseup mousemove mouseleave mouseout touchstart touchmove touchend touchcancel', this.onEvent);
      if (this.options.toolLinks) {
        $('body').delegate("a[href=\"#" + (this.canvas.attr('id')) + "\"]", 'click', function(e) {
          var $canvas, $this, key, sketch, _i, _len, _ref;
          $this = $(this);
          $canvas = $($this.attr('href'));
          sketch = $canvas.data('sketch');
          _ref = ['color', 'size', 'tool'];
          for (_i = 0, _len = _ref.length; _i < _len; _i++) {
            key = _ref[_i];
            if ($this.attr("data-" + key)) {
              sketch.set(key, $(this).attr("data-" + key));
            }
          }
          if ($(this).attr('data-download')) {
            sketch.download($(this).attr('data-download'));
          }
          return false;
        });
      }
    }
    Sketch.prototype.download = function(format) {
      var mime;
      format || (format = "png");
      if (format === "jpg") {
        format = "jpeg";
      }
      mime = "image/" + format;
      return window.open(this.el.toDataURL(mime));

    };
    Sketch.prototype.set = function(key, value) {
      this[key] = value;
      return this.canvas.trigger("sketch.change" + key, value);
    };
    Sketch.prototype.startPainting = function() {
      this.painting = true;
      return this.action = {
        tool: this.tool,
        color: this.color,
        size: parseFloat(this.size),
        events: []
      };
    };
    Sketch.prototype.stopPainting = function() {
      if (this.action) {
        this.actions.push(this.action);
      }
      this.painting = false;
      this.action = null;
      return this.redraw();
    };
    Sketch.prototype.onEvent = function(e) {
      if (e.originalEvent && e.originalEvent.targetTouches) {
        e.pageX = e.originalEvent.targetTouches[0].pageX;
        e.pageY = e.originalEvent.targetTouches[0].pageY;
      }
      $.sketch.tools[$(this).data('sketch').tool].onEvent.call($(this).data('sketch'), e);
      e.preventDefault();
      return false;
    };
    Sketch.prototype.redraw = function() {
      var sketch;
      this.el.width = this.canvas.width();
      this.context = this.el.getContext('2d');
      sketch = this;
      $.each(this.actions, function() {
        if (this.tool) {
          return $.sketch.tools[this.tool].draw.call(sketch, this);
        }
      });
      if (this.painting && this.action) {
        return $.sketch.tools[this.action.tool].draw.call(sketch, this.action);
      }
    };
    return Sketch;
  })();
  $.sketch = {
    tools: {}
  };
  $.sketch.tools.marker = {
    onEvent: function(e) {
      switch (e.type) {
        case 'mousedown':
        case 'touchstart':
          this.startPainting();
          break;
        case 'mouseup':
        case 'mouseout':
        case 'mouseleave':
        case 'touchend':
        case 'touchcancel':
          this.stopPainting();
      }
      if (this.painting) {
        this.action.events.push({
          x: e.pageX - this.canvas.offset().left,
          y: e.pageY - this.canvas.offset().top,
          event: e.type
        });
        return this.redraw();
      }
    },
    draw: function(action) {
      var event, previous, _i, _len, _ref;
      this.context.lineJoin = "round";
      this.context.lineCap = "round";
      this.context.beginPath();
      this.context.moveTo(action.events[0].x, action.events[0].y);
      _ref = action.events;
      for (_i = 0, _len = _ref.length; _i < _len; _i++) {
        event = _ref[_i];
        this.context.lineTo(event.x, event.y);
        previous = event;
      }
      this.context.strokeStyle = action.color;
      this.context.lineWidth = action.size;
      return this.context.stroke();
    }
  };
  return $.sketch.tools.eraser = {
    onEvent: function(e) {
      return $.sketch.tools.marker.onEvent.call(this, e);
    },
    draw: function(action) {
      var oldcomposite;
      oldcomposite = this.context.globalCompositeOperation;
      this.context.globalCompositeOperation = "copy";
      action.color = "rgba(0,0,0,0)";
      $.sketch.tools.marker.draw.call(this, action);
      return this.context.globalCompositeOperation = oldcomposite;
    }
  };
})(jQuery);

I read that this may be a limitation of HTML5. If so, is there a workaround?

Thank you in advance!!