Using Javascript FileReader with huge files

Question

I have a problem using the Javascript FileRead trying to read huge files.

For example, I have a text file of 200mb and everytime I read this file the code stops work

Answer 1

This will only read the first 10 mb:

var file = form.getEl().down('input[type=file]').dom.files[0];
var reader = new FileReader();

reader.onload = function(e) {
    var data = e.target.result;
    form.displayedData = data;
};

reader.readAsText(file.slice(0, 10 * 1024 * 1024));