Rails Trying to submit a form onchange of dropdown

this.form.submit() will not work if form is remote: true and rails-ujs is in use. In that case, a regular submit will occur instead of XHR.

Instead you should:

onchange: 'Rails.fire(this.form, "submit")'

You can read here for more details.

This is what I was able to do to get it to work. I named the form switch_car by using :name => "switch_car" and used the following javascript.

:onchange => ("javascript: document.switch_car.submit();")

I am still looking for a better answer so I will updated if I find something. This doesn't use submit .js for some reason. It processes it as HTML unlike the submit button which uses AJAX to update only the changing page elements. But this is the best I have been able to find so far.

Replace your onchange with this,

onchange: "this.form.submit();"