Update throttle2.js

Author: ishuiz

demos/throttle/throttle2.js

@@ -12,17 +12,15 @@ container.onmousemove = throttle(getUserAction, 3000);
 
 function throttle(func, wait) {
     var timeout;
-    var previous = 0;
 
     return function() {
-        context = this;
-        args = arguments;
+        var context = this;
+        var args = arguments;
         if (!timeout) {
             timeout = setTimeout(function(){
                 timeout = null;
                 func.apply(context, args)
             }, wait)
         }
-
     }
-}
+}