How to fix "xls file format does not match file permission" error?

Question

JavaScript

In general, the task is this:
Create a file on the user's side using JS excel.
I’ll make a reservation right away that this cannot be done on the server side, the only way!
I used an example for this from this site:
jsfiddle.net/kmqz9/265
However, there is a problem. When opening such a file, it gives an error "The xls file format does not match the file permission ...", please tell me how to solve this problem.

Answer 1

because the file extension does not match the content, so a warning is issued.
the file must have an .xml extension

Answer 2

The solution from the Microsoft site https://support.microsoft.com/en-us/kb/948615 helped me (Windows 7 Prof, Office 2013).