Phần này bao gồm các biểu hiện kiểu cũ, và các biểu hiện mới được mô tả trong các phần sau. Mỗi thư mục có chứa một phần gói chrome, trong trường hợp nội dung của chúng tôi, da / cổ điển, và miền địa phương / en-US, phải có một tập tin có tên . | 380 Part VI Creating Extensions and Themes If there are still things you don t completely understand you can do some real hacking you can modify the extension comment things out and add your own pieces of code. You can add dump and alert calls to examine the value ofJavaScript variables see how different functions are invoked and so on. Also you can use the technique that allows you to modify an installed extension described earlier in this chapter to make the hacking process more efficient. One of the greatest benefits of knowing how extensions work is being able to tweak existing extensions to better suit your needs. You can modify the extension UI to make it prettier or to change some of its JavaScript code to slightly adjust its behavior. If you believe that your changes might be useful to anyone besides yourself you can contact the extension author and suggest these improvements or even offer your help with the project. If you want to use in your own work the code you found in another extension or to modify it in any way first make sure that the extension license allows it. Many extensions have licenses that allow you to use their code in your extension under different conditions. Always credit the original authors for their work. Many licenses specifically require that but this is really a matter of courtesy. Also if you think that an existing extension is missing some pieces of functionality consider contacting the author and suggesting a contribution to the existing extension before creating your own derivative product. Summary This chapter explained everything you need to know to start writing your own extensions. You should now know how extensions are created packaged and distributed how different parts of Firefox can be customized using extensions and where to get further documentation and help. Once you see how simple the process of creating Firefox extensions is you might be tempted to start writing your own extension right away. Don t resist this .
