The suggest wizard in TCEforms within jsfunc.tceforms_suggest.js is a wrapper for Prototype/Ajax.
This should be migrated over to jQuery.
Updated by Andreas Wolf about 6 years ago
My current WIP branch for this is here: https://github.com/andreaswolf/TYPO3.CMS/tree/task/tceforms-suggest-jquery
This is not only a jQuery migration, but also a general refactoring of this feature to put it to a more solid base.