How to validate forms in simple projects?

Question

JavaScript

In projects that are written in React, I use redux-form, formic, yup (depending on the task) ... These technologies, thanks to documentation, clear examples and structure, give quite suitable architecture techniques for validating both large and small forms ...
What techniques, technologies can be used in projects that are written in native js?
PS At the moment, in some projects, there are many self-written crutches for validation. that I would like to get rid of...