I can make sense of the errors, some browsers want only asynchronous AJAX requests (first A sic :) and you get a timing problem (the type shouldn't be touched before the answer arrived)

I already had to adapt some JS code.

You should file a bug report.

Personally I prefer binding bookmarklets to keywords, works great in FF though no idea of chrome.¹

update

¹) I thought you were talking about a search add on for your browser.