JSFiddle - React, Tailwind, and code Playground

by Castrolol

HTML

<input type="file" id="fileinput" />

JavaScript

function readSingleFile(evt) {
    //Retrieve the first (and only!) File from the FileList object
     
    var f = evt.target.files[0]; 

    if (f) {
      var r = new FileReader();
      r.onload = function(e) { 
           debugger;
          var contents = e.target.result;
        alert( "Got the file.\n" 
              +"name: " + f.name + "\n"
              +"type: " + f.type + "\n"
              +"size: " + f.size + " bytes \n"
              + "starts with: " + contents.substr(1, contents.indexOf("\n"))
        );  
      }
      r.readAsText(f);
    } else { 
      alert("Failed to load file");
    }
  }

  document.getElementById('fileinput').addEventListener('change', readSingleFile, false);