Why am I getting "strict MIME type checking is enabled." at re-route of the user?

Question

Node.js

Hello!
I created this route:

<Route path="/dictionary/:lang" component={Dictionary} />

I go to it like this:

<Link to={`dictionary/${item.toLowerCase()}`} className={[classes.flex, classes.link].join(" ")}>

item.toLowerCase() - a regular string like "russian"
When I try to reroute here, I get :

and the project crashes.
Other routes work.
This is my first time using a route with the :lang parameter, maybe because of this?
Thanks

Answer 1

It is possible that the public path is not specified in the webpack config:

module.exports = {
    ...
    output: {
        publicPath: '/'
    }
}

The right way:
to={`/dictionary/${item.toLowerCase()}`}

Answer 2

if ($(".select_menu").val() == "23"){
you have an assignment sign, not an equality test

$(function() {    
    if ($(".select_menu").val() == "23"){
        $('.form_input.hidden').addClass('active');
    }
});

Answer 3

Need an example. For now, offhand, I can assume that the DIV is initially hidden. It is possible that the class is added, but in addition to this, the .hidden class must also be removed for it to be displayed.