Flask get checkbox value without submit button

I’m trying to get value of checkbox in flask without a submit.

here is my app.py

from flask import Flask, render_template, request

app = Flask(__name__)

@app.route('/', methods=['GET', 'POST'])
def index():
    if request.form.get('c_check')=="0":
        print('success: 0')
        checked=''
    elif request.form.get('c_check')=="1":
        print('success: 1')
        checked='checked'
    return render_template('index.html')

Here is my javascript that toggle the checkbox:

function hello(){
    if (document.querySelector('input').value=='0'){    
        document.querySelector('input').value='1'
        console.log('value 1');
    }
    else {
        document.querySelector('input').value='0'
        console.log('value 0');
}

}

And here is my index.html

<form method="post" action="">

    <div class="form-check form-switch">
        <input class="form-check-input btn-lg" 
        name="c_check" 
        value="0" 
        type="checkbox" 
        role="switch" 
        id="flexSwitchCheckChecked" 
        onclick="hello()"
        >
        
        <label class="form-check-label btn-lg" 
        for="flexSwitchCheckChecked"></label>
        <input type="submit">
    </div>
</form>

<script src="{{url_for('static', filename= 'js/hello.js')}}"></script>

I want to

1. Remove the submit button
2. When I click on the checkbox, python should receive the checkbox value, 0 or 1.

The present code only returns 1 when I click the submit button. The solution should be that I remove the submit button entirely and have python listen on the value change and print that in real time.

I’m open to socketio solution, but I don’t know how to do it.

Thank you for your help.