If you create an Excel file using an HTML Table, then it exists a way to format the cells based on some CSS rules. Some examples can be found on this blog post.
I spent some time trying to figure out how to display correctly the dates, whatever your regional settings are ; for exemple in the USA the format is MM/dd/YYYY, and for the rest of the world is dd/MM/YYYY.
Finally I found that the content of the date cells must always be defined with the same format : YYY-MM-dd HH:mm, and then we can apply a style like mso-number-format:"dd\-mmm\-yyyy\ hh\:mm".
Example:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | <html><head><style>br {mso-data-placement:same-cell} .xls-date {mso-number-format:"dd-mmm-yyyy hh:mm"}</style></head><body> <table> <tr> <th>Event Name</th> <th>Event Date</th> </tr> <tr> <td>Birthday Party</td> <td class="xls-date">2015-11-01 10:00</td> </tr> </table></html> |
So the date cell will display: 01-Nov-2015 10:00 and will be interpreted as a Date cell by Excel.