The following use of Windows browser Google Chrome teaching demonstration, the interface may also slightly different on different versions, but the main mode of operation should not be too unfamiliar, if you want a browser plug-export on their own computer, you can try shining a look at the operations herein.
1, first of all, from the menu to find "additional tools", click "extensions" open management tools, or directly in the address bar enter chrome: // extensions / can reach the same page. 
Next, the "Developer mode" to open the upper right corner, you can see the ID of each extension, the first plug-in that you want to back up the numbers to remember. 
2, open the file archive, enter the path to the top: C: \ Users \ UserName \ AppData \ Local \ Google \ Chrome \ User Data \ Default \ Extensions, remember to change your user name UserName, so you can see all installed extensions folder. 
The first step in the control plug-in number noted down, find the corresponding folder, click into the layer name will then see the version number of the directory, the directory structure will be like the figure below, including some pictures and related files will be used in the plug, tap the top of the path, copy down the full path.
3, back to the Google Chrome Extensions page, upper right corner "Developer mode" open, select the middle of the "package extensions."
Just copy paste the path "Extension root directory" column, the private key file is left empty, press the "package extensions."
4, the right words will appear "has established the following file" message, Google Chrome will add the directory package, and .pem .crx into two files.
Returns Explorer, back up a layer of plug-in folder you will find two .crx and .pem file, move the file to a different path to the backup storage, such as your Drive. If you need to reinstall the future expansion of the program, even if you have Chrome application store from the shelves, you can still .crx drag files into Google Chrome browser installed plug-in function. With offline installation chrome plug-in approach is consistent.
5, often encounter a situation "package extension error", if the display for specified extension already private key, use the key or delete it first, or similar problem can not export plug-in, usually the third step is to paste the path of the plug-in error, please remember to switch the version number into the directory, then complete copy down the path, otherwise an error will occur.