Excel files will show in the browser if Microsoft Excel be installed on the visitor's computer...If a visitor hasn't an installed version of Microsoft Excel so he can't see the file in the browser , and the browser hasn't any another way except bring a download box for him ...
You can put the contents of excel file in a content item ...
EDIT: The contents of the excel file cannot be imported in a content item. The excel file has a mathematic execution (a simple SUM). I tried to put the contents (saved the excel as html and after that got the code into elxis content item), but the execution didnt work.
Well, the best solution i have came up is this:1) Create an excel sheet/book and save using "Save as Web Page" together with the option "Add interactivity" selected. 2) Upload to a folder in the Elxis site3) Create item menu wrapper.