Hi Price Caspion

To give you a proper answer I will need more details about when it's needed the value of active_id and what kind of wizard are you launching, but assuming stuffs, here is some notes:

1- A normal Odoo wizard it's a form that contain fields, one field could have the value of the active_id as a default captured on the field default definition

@api.model 
def _get_active_id(self):
    return self._context.get('active_id')

deploy_config_id = fields.Many2one('res.partner', string='Customer', required=True, default=_get_active_id)

2- If you really need to get the value on JS here is a way that might work for you, depending of what you are doing 

var dataset = this.dataset;
var active_id = dataset.ids[dataset.index];

If your js code is executed on the form view of the wizard or something this.dataset will have the dataset where the dataset index is the position to the current record id in the dataset.ids array. If not is the case find a the proper dataset path to get the value using js debug using chrome developer tools or any similar tool for your browser

Hope this help you