what software are you talking about??
You might want to ask in the PhotoShop LightRoom forum.
If you click on the big yellow "Download" button and you may need to login to with Adobe ID to start the download of the JS file. You may have to wait for the entire web page to download and be processed by your computer before the button could be active.
Have you set and high security levels or disabled some interactive features in your browser?
If the file was posted with a text file type, then it would almost always download but the end user would need to rename the file. This can be daunting to some.