Fixed "Hide placeholders of blocked elements" feature

include.preload.js

 /*
  * This Source Code is subject to the terms of the Mozilla Public License
  * version 2.0 (the "License"). You can obtain a copy of the License at
  * http://mozilla.org/MPL/2.0/.
  */
 
 var SELECTOR_GROUP_SIZE = 20;
 
 var elemhideElt = null;
 
@@ skipping 43 matching lines @@
     {
       case "hide-element":
         if (request.documentUrl != document.URL)
           return;
 
         // We have little way of knowing which element was blocked - see
         // http://code.google.com/p/chromium/issues/detail?id=97392. Have to
         // look through all of them and try to find the right one.
         var remove = [];
         var elements = (request.type == "IMAGE" ? document.images : document.getElementsByTagName("iframe"));
-        for (var i = 0; i < elements.length; i++)

[Thomas Greiner, 2012/10/26 14:21:54]

don't access elements.length on each iteration (create a variable for it before
the loop)

+        for (var i = 0, l = elements.length; i < l; i++)
           if (elements[i].src == request.url)
             remove.push(elements[i]);

[Thomas Greiner, 2012/10/26 14:21:54]

we could break after we found one element

[Wladimir Palant, 2012/10/26 14:34:23]

I don't think we should, it isn't necessarily a single element.

 
-        for (var i = 0; i < remove.length; i++)

[Thomas Greiner, 2012/10/26 14:21:54]

not as important as with elements.length but still not a bad thing to do:
don't access remove.length on each iteration (create a variable for it before
the loop)

+        for (var i = 0, l = remove.length; i < l; i++)
           if (remove[i].parentNode)
             remove[i].parentNode.removeChild(remove[i]);
     }
   });
 
   chrome.extension.sendRequest({reqtype: "get-settings", selectors: true, frameUrl: window.location.href}, function(response)
   {
     setElemhideCSSRules(response.selectors);
   });
 }
 
 // In Chrome 18 the document might not be initialized yet
 if (document.documentElement)
   sendRequests();
 else
   window.setTimeout(sendRequests, 0);