How to gain javascript data from a file using a filereader api

Question

I do not understand why this code is not working I am new to coding in javascript and I can't figure out the filereader.

var reader = new FileReader();
reader.onload = function {
var data = reader.result;
alert(data);
};
reader.readAsText("file:///C:/test.txt");

Answer 1

simply put, you cannot access the clients Filesystem with javascript. it's a security measure. you can't use the file protocol.