JSFiddle - React, Tailwind, and code Playground

by ajai jothi

HTML

<input type="file" id="uploadDoc">

JavaScript

document.getElementById('uploadDoc').onchange = function(e){
	if(!validateFile(e.target.files[0])){
  	alert('invalid file');
    e.target.value = '';
    return false;
  }
};

function validateFile(file){
  var allowExtn = ['doc','docx','txt','pdf']; //input allowed file extn here
  var fName = file.name;
  var ext = fName.split('.').slice(-1).join('');
  debugger;
  return allowExtn.indexOf(ext)>=0;
}