| Index: composer.js | 
| diff --git a/composer.js b/composer.js | 
| index fc8e9ccaf6e0e13baeb2b5f166bf7b4f45625405..6c54eff99dd0775af4f9262f61defc7be4dd1ad7 100644 | 
| --- a/composer.js | 
| +++ b/composer.js | 
| @@ -15,7 +15,9 @@ | 
| * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>. | 
| */ | 
|  | 
| -var targetPageId = null; | 
| +"use strict"; | 
| + | 
| +let targetPageId = null; | 
|  | 
| function onKeyDown(event) | 
| { | 
| @@ -38,7 +40,7 @@ function addFilters() | 
| type: "filters.importRaw", | 
| text: document.getElementById("filters").value | 
| }, | 
| -  function(errors) | 
| +  errors => | 
| { | 
| if (errors.length > 0) | 
| alert(errors.join("\n")); | 
| @@ -77,7 +79,7 @@ function init() | 
|  | 
| document.getElementById("filters").focus(); | 
|  | 
| -  ext.onMessage.addListener(function(msg, sender, sendResponse) | 
| +  ext.onMessage.addListener((msg, sender, sendResponse) => | 
| { | 
| switch (msg.type) | 
| { | 
|  |