function parseVisibleItems(chart, handler) {
	var metasets = chart._getSortedVisibleDatasetMetas();
	var metadata, i, j, ilen, jlen, element;

	for (i = 0, ilen = metasets.length; i < ilen; ++i) {
		metadata = metasets[i].data;
		for (j = 0, jlen = metadata.length; j < jlen; ++j) {
			element = metadata[j];
			if (!element._view.skip) {
				handler(element);
			}
		}
	}
}
Helper function to traverse all of the visible elements in the chart
@param {Chart} chart - the chart
@param {function} handler - the callback to execute for each visible item