Foxit PDF Editor allows you to extend its capabilities with a custom-made JavaScript Plugins. If you have an existing JS Plugin from Adobe Acrobat or other PDF software, you may be able to use it with Foxit PDF Editor.
To install simply copy > paste your existing JS Plugin file 
to:
"~AppData\Roaming\Foxit Software\Foxit PDF Editor\JavaScript" (requires admin rights)
or
"C:\Program Files (x86)\Foxit Software\Foxit PDF Editor\Javascripts"
And that's it!
Your Plugin will show either under the "Home Tab" or "Forms Tab" in Foxit PDF Editor. See example below:
If your JS Plugin does not work as expected utilize our JavaScript API Manual to debug issues. (attached)
