how can i create get request unis ajax without expecting return value

i have correct my Code and it works now.

Order.prototype._downloadDetails = function () {
                    
        var sServiceUrl = _oController.getServiceUrl();
        let iRoleId = _oController.getRoleId();
        let iObjectId = _oController.getObjectId();

        if (sServiceUrl && iRoleId && iObjectId) {
                window.open(sServiceUrl
                    +"/download?"
                    + "roleId=" + iRoleId
                    + "&objectId=" + iObjectId, '_blank').focus()
        }
    };