alert without jquery

js/src/dom/selectorEngine.js

@@ -0,0 +1,42 @@
+/**
+ * --------------------------------------------------------------------------
+ * Bootstrap (v4.0.0-beta): dom/selectorEngine.js
+ * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
+ * --------------------------------------------------------------------------
+ */
+
+const SelectorEngine = {
+  matches: Element.prototype.msMatchesSelector || Element.prototype.webkitMatchesSelector,
+
+  find(selector) {
+    if (typeof selector !== 'string') {
+      return null
+    }
+
+    let selectorType = 'querySelectorAll'
+    if (selector.indexOf('#') === 0) {
+      selectorType = 'getElementById'
+      selector = selector.substr(1, selector.length)
+    }
+    return document[selectorType](selector)
+  },
+
+  closest(element, selector) {
+    let ancestor = element
+    if (!document.documentElement.contains(element)) {
+      return null
+    }
+
+    do {
+      if (SelectorEngine.matches.call(ancestor, selector)) {
+        return ancestor
+      }
+
+      ancestor = ancestor.parentElement
+    } while (ancestor !== null)
+
+    return null
+  }
+}
+
+export default SelectorEngine