Board Thread:Support Requests - Getting Technical/@comment-10637-20200628124758/@comment-26611127-20200628192002

The inputbox extension does not have this feature, and I'm not aware of any script on the Dev Wiki that does either.

I'm sure it's possible, as I've created YouTube search widgets to place on various wikis, but you would have to use JavaScript.

This Google article could provide you with a foundation for your widget: Google Custom Search Engines.