Someone

function cal_popup1 (str_datetime) {
        if (str_datetime) {
                this.dt_current = this.prs_tsmp(str_datetime);
        }
        else {
                this.dt_current = this.prs_tsmp(this.target.value);
                this.dt_selected = this.dt_current;
        }
        if (!this.dt_current) return;

        var obj_calwindow = window.open(
                'calendar.html?datetime=' + this.dt_current.valueOf()+ '&id=' + this.id,
                'Calendar', 'width=240,height='+(this.time_comp ? 215 : 190)+
                ',status=no,resizable=no,top=(window.event.clientY),left=(window.event.clientX),dependent=yes,alwaysRaised=yes'
        );
        obj_calwindow.opener = window;
        obj_calwindow.focus();
}