How Can A Local Text File Be Read In The Browser Using JavaScript?

To read a local text file in the browser using JavaScript, you can make use of the FileReader API. Here’s an example:

<input>

<script>
    document.getElementById('fileInput').addEventListener('change', function(event) {
        var file = event.target.files[0];
        var reader = new FileReader();

        reader.onload = function(e) {
            var contents = e.target.result;
            console.log(contents); // Displaying the contents of the file

            // Do further processing with the file contents    
        };

        reader.readAsText(file);
    });
</script>

In this example, an input element of type ‘file’ is used to allow the user to select a local text file. When the user selects a file, the "change" event handler is triggered.

Inside the handler, we obtain the selected file using event.target.files[0], and create a new instance of the FileReader using new FileReader(). We then define the onload event handler, which is called when the file has been loaded successfully.

Inside the onload handler, e.target.result contains the contents of the file as a string, which can be processed further as needed. In the example, we simply log the contents to the console.

Finally, we call reader.readAsText(file) to initiate the reading of the file as text.

About the Author Rex

I'm a passionate tech blogger with an insatiable love for programming! From my early days tinkering with code, I've delved into web dev, mobile apps, and AI. Sharing insights and tutorials with the world is my joy, connecting me to a global community of like-minded tech enthusiasts. Python holds a special place in my heart, but I embrace all challenges. Constantly learning, I attend tech conferences, contribute to open-source projects, and engage in code review sessions. My ultimate goal is to inspire the next generation of developers and contribute positively to the ever-evolving tech landscape. Let's code together!