Grid init

docs/lib/grid.js

@@ -0,0 +1,17 @@
+'use strict';
+
+document.addEventListener('DOMContentLoaded', function () {
+
+  var $cells = getAll('.cell');
+
+  $cells.forEach(function (el) {
+    var parentWidth = el.parentElement.offsetWidth;
+    var percentage = el.offsetWidth / parentWidth * 100;
+    el.append('' + Math.round(percentage));
+  });
+
+  // Functions
+  function getAll(selector) {
+    return Array.prototype.slice.call(document.querySelectorAll(selector), 0);
+  }
+});