How to customize the Powermail javascript without the risk to overwrite it with the next update? To be specific: I would like to change the ajax function of Powermail Version 3.6.0.
Is there a possibility to move the javascript into my template extension like it is possible with typoscript?
plugin.tx_powermail.view.templateRootPaths.10 = ...
Depending on which typoscript setup are you including from the powermail extension. For the standard one should be something like: page.includeJSFooter.powermailForm
You can find non-minified versions of javascript you want to override in Resources/Private/JavaScripts folder.