How does the search function work in the Acrobat JavaScript API Reference?

I visit the site
https://opensource.adobe.com/dc-acrobat-sdk-docs/library/jsapiref/index.html 

almost every day. Finding something specific there is quite tedious. Most of the time, Google search takes me to the right place.

The search field in the top left corner of the Reference does not work for me, neither in Firefox nor in Internet Explorer nor in Google Crome.
Is there a trick to making this search work? How do you do it?