Full example how to get, in javascript, field_values array, model, ids and id in backend form:

inherited XML:

<div id="target">Click here</div> 

Javascript:

openerp.my_module = function(instance) {

  instance.web.FormView = instance.web.FormView.extend({
      events: {
          'click #target button': 'button_clicked',
      },      
      
      button_clicked: function(ev) {   
          ev.preventDefault();
          ev.stopPropagation();
          
          var field_values = this.get_fields_values();
          var ids = this.get_selected_ids();
          var id = field_values['id']
          var model = this.model
                    
          openerp.jsonRpc('/my_module/example/, 'call', { model: model, ids: ids, id: id}).then(function (data) {
            ...my code...
          });
          
      },
  });

}