SheetJS Data Preview Live Demo
(Base64 text works back to IE6; drag and drop works back to IE10)

Source Code Repo
Issues?  Something look weird?  Click here and report an issue
Output Format: 
 CSV
 JSON
 FORMULAE
 HTML


Drop a spreadsheet file here to see sheet data
 ... or click here to select a file

... or paste a base64-encoding here


Advanced Demo Options: