JSX files are simple text files that can be opened and edited with any text editor. For development, Adobe offers the ExtendScript Toolkit for free download. Self-developed or downloaded JSX files should be stored under 'Preferences / Scripts', (if not available, simply create them) so that the program (eg Photoshop) finds them. After restarting the program, the scripts should be accessible via 'File -> Scripts'.
In the newer versions of the Adobe products (CS3 and higher) you can also use 'File-> Scripts' to 'browse' to select a JSX file. The procedure may be different for some Adobe products.
Most often resolving problems with opening JSX files is very simple. Just install an appropriate program that supports such files. All of the listed programs support JSX files, but may vary in offered function and purpose. Some programs may be capable only of viewing contents of JSX files or offer file conversion options, but may not be capable of editing such files.
It is possible that although a compatible program has been installed on user’s system, it is not used by the system to open it. This may happen because no default application was associated with this type of files. To associate JSX files with given application, select "Open with" from drop-down menu (accessed by right-clicking on the file). Then select from the list the program or application you want to be used to open this type of file. If the Adobe After Effects applications is not on the list, select "Browse" option in order to manually locate the directory where Adobe After Effects has been installed.
Sometimes problems with opening JSX files may not lie with the application itself, but can arise due to other causes, such as: