How to open a local disk file with JavaScript and check whether it has the word which we needed?

Question

I want to open text or word file in JavaScript. After that I want my program to scan that whether it has the word which i needed. If it has the world then it should produce an alert as word is found,else alert as word is not found. Please help me in this. I wrote an code to read from file.But I'm not sure where the content of file is stored and where to use search function.

My current code is

<h1>File reader</h1>
<div>
    Select a text file: 
    <input type="file" id="fileInput">
    <pre id="displayArea"><pre>
</div>

window.onload = function() {
    var fileInput = document.getElementById('fileInput');
    var displayArea= document.getElementById('fileDisplayArea');

    fileInput.addEventListener('change', function(e) {
        var file = fileInput.files[0];
        var textType = /text.*/;

        if (file.type.match(textType)) {
            var reader = new FileReader();

            reader.onload = function(e) {
                displayArea.innerText = reader.result;
            }
    reader.readAsText(file);                

        } else {
            displayArea.innerText = "File not supported!"
        }
  });
}

by using this I can get my file content in output,But I need output as an alert whether file has the needed word.

Answer 1

You are doing nothing with your result, thats why you have to store the reader.result output in a variable, then look if the word you are looking for is inside of that output and show the alert.

Something like this...

var readResult = reader.result;

if (/Hello/.test(readResult)) {
  alert("The word exist");
} else {
  alert("The word does not exist");
}