improving on issue chuanxshi#42 changed == to ===

Author: chuanxshi

function-patterns/callback.html

@@ -19,7 +19,7 @@
 				var node = complexComputation();
 
 				// call if callback is callable
-				if (typeof callback == "function") {
+				if (typeof callback === "function") {
 					callback(node);
 				}