tl;dr; you can't, cause the fibers are crinckled up in a lower energy state, but try soaking in 1 tablespoon of hair conditioner per liter of lukewarm water and stretch.
I assume you mean htmx. It doesn't have to be either/or. You can supplement htmx with Javascript.
The core idea with htmx is that you transfer hypertext with controls and structure built in, not just a JSON blob that requires additional context to be useful.
I have just shipped a very useful and interactive app surprisingly quickly for my customer using just htmx with a little Javascript.