Read File from browser using XMLHttpRequest

read-file.js

 function readTextFile(file) {
    var rawFile = new XMLHttpRequest();
    rawFile.open("GET", file, false);
     
    rawFile.onreadystatechange = function () {
    if(rawFile.readyState === 4) {
        
    if(rawFile.status === 200 || rawFile.status == 0) {
        var allText = rawFile.responseText;
           doSomethingWithTheText(allText);
        }   
    }
        
    } 
     rawFile.send(null);
 }