How to pass parameters on onChange of html select with flask-wtf

The following flask code creates a select .. option dropdown menu: model: class SelectForm(Form): country = SelectField('Country', choices=[ ('us','USA'),('gb','Great Britain'),('ru','Russia')]) flask app: @app.route('/new') def new(): form = SelectForm() return render_template('new.html', form = form ) html file: <form method=post action="/register"> {{ render_field(form.country) }} <p><input type=submit value=Register> </form> macro file the defines render_field: {% macro render_field(field) %} <dt>{{ field.label }} <dd>{{ field(**kwargs)|safe }} {% if field.errors %} <ul class=errors> {% for error in field.errors %} <li>{{ error }}</li> {% endfor %} </ul> {% endif %} </dd> {% endmacro %} What is the best way to have onchange submit the results automatically without the user having to press the submit button? Is there a way to change the macro or what's the most elegant way? thanks