Web and WebWorks Development

[huydq5000]

I have to read top n bytes of a set of very big files in the system in my WebWorks app but I don't know how to implement it. Please help me.

Thanks

[haahmad · Accepted solution]

Hi huydq5000, 

Using the FileReader you can use the function called readAsBinaryString(blob)

Suppose you had a File object named file and a FileReader object named reader.

You can use file.slice(startByte, endByte) to obtain a Blob chunk of your File object, in your case it would be something like:

reader.readAsBinaryString(file.slice(0, n));

Take a look at the "Slicing a File" section in this link:
http://www.html5rocks.com/en/tutorials/file/dndfiles/