Hi there,
I will create a page were you can insert the code and it will be changed instantly on your Wix website I can make the page could run from anywhere and ever from your computer I can also add login and register system in case you wanted more than one user to use it, and it doesn't have to be one input changed one element in the website, if you have more elements that you want their content managed the same way we can add them too.
best regards,
Ahmed.