This template checks if after the patient signed informed consent (date1) a visit has taken place (date2) between a day range.

In this template:

• date1 and date2 are two date fields in your form. Replace them with your own variable names. 
• XX and YY are the limits you want to use. Replace them with the number of days you want to check for, e.g. 0 and 14.

var dateDiff = getDateDiff('{date1}','{date2}', 'day');
if(dateDiff > XX || dateDiff < YY){
"Difference between date1 and date2 has to be between XX and YY days,
it's currently " + dateDiff + " days.";
}