Validating dates in excel
Note: If you aren't using a named table, follow the instructions to Prevent Duplicates in a Range The named table will have four columns, and drop down arrows in the header row.
You can prevent users from adding ANY spaces in the cell -- whether the entry is text, numbers, or a combination of both. The FIND function looks for the space character - " " - and the ISERROR function result is TRUE, if the space character is not found.
The cell with the value (B3) is a relative reference -- it should change in each cell.