I need to open a PDF in browser and have it print automatically

Hello, it looks like this is possible, as i've found numerous examples of how to do this, but it seems like Acrobat DC makes this prohibitively difficult compared to all the tutorials I've found. So far, i've tried to open the document, open the action wizard, create a new action to execute javascript, and added a javascript file with the following code:

function printOnOpen() {
  this.print({bUI: false, bSilent: true, bShrinkToFit: true});
}
printOnOpen();

But when I click "Start" acrobat fails on me. Any tips?

Thanks