E01T · July 13, 2013 07:23 · Jul 13, 2013
diff --git a/array_index_of.js b/array_index_of.js
@@ -0,0 +1,15 @@
+/*
+  If you have worked with JavaScript at any length you are aware that IE does not implement 
+  the ECMAScript function for Array.prototype.indexOf() [including IE8]. Not a huge problem 
+  because you can extend the functionality on your page with the following code.
+*/
+if (!Array.prototype.indexOf) {
+
+  Array.prototype.indexOf = function(obj, start) {
+     for (var i = (start || 0), j = this.length; i < j; i++) {
+         if (this[i] === obj) { return i; }
+     }
+     return -1;
+  }
+
+}