Using JS, the field in the view is updated, but pressing the save button does, not save the value in the field.

JS code:

var FormController = require('web.FormController');
    FormController.include(
    {
        _onButtonClicked: function (event) 
        {
            if(event.data.attrs.id === "action_addpoint")
            {	                    
                $("input[name='points'].o_input_points")
                    .val("save_a_modified_field_with_JS")
                    .focus()
		            .change();
            }            
        },
    });

XML Code:

<header>
        <button id="action_addpoint" string="Add point"/>
    </header>
    <group  col="4">
        <field name="points" class="points"/>
    </group>