Using this extension you will be able to inject javascript codes into webpages, in order to customize your most visiting websites, to have a more comfortable web browsing.
Unfortunately I am not able to deploy this extension on Google Web Store, because Google doesn't have any payment methods available for my country, So I can not pay first time $5 registeration fee.
In order to install this extension go to your extension page at chrome://extensions/, then drag and drop JS-Injector.crx into that page.