SheetJS JS-CRC32 Live Demo
(text works back to IE6; drag and drop works back to IE10)
(This demo loads the entire file at once!  For newer browsers, try the large file demo)

Source Code Repo
Issues?  Something look weird?  Click here and report an issue

Drop a text file to compute the CRC-32 checksum
... or click here to select a file
Advanced Demo Options: Use readAsBinaryString: (when available)