Add grid interactions

docs/lib/playground.js

@@ -0,0 +1,23 @@
+"use strict";
+
+document.addEventListener("DOMContentLoaded", function () {
+  var $grid = document.getElementById("grid");
+  var $columns = document.querySelectorAll(".jsColumns");
+
+  $columns.forEach(function ($) {
+    return $.addEventListener("input", function (event) {
+      var count = event.target.valueAsNumber;
+      var suffix = event.target.dataset.suffix;
+      console.log("Column count", count);
+      $grid.className = "grid has-" + count + "-cols" + suffix;
+      var $columnsCount = getAll("strong", $.parentNode);
+      $columnsCount.innerHTML = count;
+    }, false);
+  });
+
+  function getAll(selector) {
+    var parent = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : document;
+
+    return Array.prototype.slice.call(parent.querySelectorAll(selector), 0);
+  }
+});