There some buggy JavaScript in iDreamLibraries / iDreamBooks that you get by turning on the iDreamBooksResults rating results. Having this on breaks all JS on the OPAC results page. Relevance sorting is being impacted and even stuff like "did you mean" won't work. TypeError: $.browser is undefined opac-search.pl line 6340 position 17 (edited) you get it by turning on IDreamBooksResults
See bug 24854, it has been removed as it's no longer working. *** This bug has been marked as a duplicate of bug 24854 ***
> it has been removed as it's no longer working. To be more specific: The service seems to be completely defunct, so fixing this problem in stable versions of Koha is not really worth the effort. The feature should be turned off in existing installations.