strStartDate will be your start date
strEndDate will be your end date
First thing we do is set the default value for whether or not we found your string. Next we find the difference between your start and end date in days, we then loop through every day between the start and end date. We use the DateAdd function to determine how far into the loop we are from the start, then we search the MyText string for the date found with the DateAdd function. If we find it, we set the boolDateFound variable to True and exit the loop.
<%
boolDateFound = False
For intDateDiff = 0 to DateDiff("d",strStartDate,strEndDate)
arrDateParts = Split(DateAdd("d",intDateDiff,strStartDate),"/")
If arrDateParts(1) <= 9 Then
arrDateParts(1) = "0" & arrDateParts(1)
End If
strCheckDate = arrDateParts(0) & "/" & arrDateParts(1) & "/" & arrDateParts(2)
Response.Write "Date: " & strCheckDate
If InStr(MyText, strCheckDate) > 0 Then
boolDateFound = True
Exit For
End If
Next
If boolDateFound Then%>
Found!
<%Else%>
Not Found
<%End If%>