diff --git a/source/extensions.js b/source/extensions.js
index 86758d5..e6bbc8b 100644
--- a/source/extensions.js
+++ b/source/extensions.js
@@ -1,5 +1,145 @@
-// NOTE Having issues conflicting with jQuery stuff when setting Object 
-// prototype settings; instead add into Liquid.Object.extensions and use in 
+// Array.indexOf
+if (!Array.prototype.indexOf) {
+  Object.defineProperty(Array.prototype, 'indexOf', {
+    enumerable: false,
+    value: function(obj) {
+      for (var i=0; i<this.length; i++) {
+        if (this[i] == obj) return i;
+      }
+
+      return -1;
+    }
+  });
+}
+
+// Array.clear
+if (!Array.prototype.clear) {
+  Object.defineProperty(Array.prototype, 'clear', {
+    enumerable: false,
+    value: function() {
+      this.length = 0;
+    }
+  });
+}
+
+// Array.map
+if (!Array.prototype.map) {
+  Object.defineProperty(Array.prototype, 'map', {
+    enumerable: false,
+    value: function(fun /*, thisp*/) {
+      var len = this.length;
+      if (typeof fun != "function")
+        throw 'Array.map requires first argument to be a function';
+
+      var res = new Array(len);
+      var thisp = arguments[1];
+      for (var i = 0; i < len; i++) {
+        if (i in this)
+          res[i] = fun.call(thisp, this[i], i, this);
+      }
+
+      return res;
+    }
+  });
+}
+
+// Array.first
+if (!Array.prototype.first) {
+  Object.defineProperty(Array.prototype, 'first', {
+    enumerable: false,
+    value: function() {
+      return this[0];
+    }
+  });
+}
+
+// Array.last
+if (!Array.prototype.last) {
+  Object.defineProperty(Array.prototype, 'last', {
+    enumerable: false,
+    value: function() {
+      return this[this.length - 1];
+    }
+  });
+}
+
+// Array.flatten
+if (!Array.prototype.flatten) {
+  Object.defineProperty(Array.prototype, 'flatten', {
+    enumerable: false,
+    value: function() {
+      var len = this.length;
+      var arr = [];
+      for (var i = 0; i < len; i++) {
+        // TODO This supposedly isn't safe in multiple frames;
+        // http://stackoverflow.com/questions/767486/how-do-you-check-if-a-variable-is-an-array-in-javascript
+        // http://stackoverflow.com/questions/4775722/javascript-check-if-object-is-array
+        if (this[i] instanceof Array) {
+          arr = arr.concat(this[i]);
+        } else {
+          arr.push(this[i]);
+        }
+      }
+
+      return arr;
+    }
+  });
+}
+
+// Array.each
+if (!Array.prototype.each) {
+  Object.defineProperty(Array.prototype, 'each', {
+    enumerable: false,
+    value: function(fun /*, thisp*/) {
+      var len = this.length;
+      if (typeof fun != "function")
+        throw 'Array.each requires first argument to be a function';
+
+      var thisp = arguments[1];
+      for (var i = 0; i < len; i++) {
+        if (i in this)
+          fun.call(thisp, this[i], i, this);
+      }
+
+      return null;
+    }
+  });
+}
+
+// Array.include
+if (!Array.prototype.include) {
+  Object.defineProperty(Array.prototype, 'include', {
+    enumerable: false,
+    value: function(arg) {
+      var len = this.length;
+
+      return this.indexOf(arg) >= 0;
+      for (var i = 0; i < len; i++) {
+        if (arg == this[i]) return true;
+      }
+
+      return false;
+    }
+  });
+}
+
+// String.capitalize
+if (!String.prototype.capitalize) {
+  String.prototype.capitalize = function() {
+    return this.charAt(0).toUpperCase() + this.substring(1).toLowerCase();
+  };
+}
+
+// String.strip
+if (!String.prototype.strip) {
+  String.prototype.strip = function() {
+    return this.replace(/^\s+/, '').replace(/\s+$/, '');
+  };
+}
+
+
+// NOTE Having issues conflicting with jQuery stuff when setting Object
+// prototype settings; instead add into Liquid.Object.extensions and use in
 // the particular location; can add into Object.prototype later if we want.
 Liquid.extensions = {};
 Liquid.extensions.object = {};