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:
                    Use Web Workers: (when available) 
                    Use readAsBinaryString: (when available)