The JavaScript should be included in the bottom of the BODY, not in the HEAD. This is for two reasons:
The loading/parsing of the HTML after the JavaScript is blocked until the JavaScript is loaded and executed. So it is recommended to put the JavaScript last thing in the BODY so that the page can be displayed quicker.
mkforms will break if other extensions provide jQuery and include it the BODY (as recommended) instead of in the HEAD.
The JavaScript should be included in the bottom of the BODY, not in the HEAD. This is for two reasons:
In TYPO3, jQuery & Prototype should be included with page.includeJSFooterlibs, and non-library mkforms stuff be included with page.includeJSFooter: https://docs.typo3.org/typo3cms/TyposcriptReference/Setup/Page/Index.html