Hide/Show a workflow rule field based on a checkbox

SOLVED

I am trying to hide or show a date and time field based on a checkbox being ticked or not. Currently, I have the below script in OnChange for the checkbox, but it only removes the date box, not the caption or the time box. 

if (crm('oppo_aftercarecall').val() == false)
{
oppo_aftercarecalldate.style.visibility = 'hidden';
}
else
{
oppo_aftercarecalldate.style.visibility = 'visible';
}

The other problem with this is that it doesn't hide the date/time field by default when the checkbox isn't ticked. 

Can anyone suggest the best way to achieve this in CRM 2018 R3?