Check the file type before Upload

Javascript Course

<h4>Example Check the file type before Upload</h4>
<p>File types allowed: PDF, GIF, JPE, and JPG:</p>

<form action='upload.php' method='post' id='idf' enctype='multipart/form-data'>
 Upload file: <input type='file' name='fup' onchange="checkName(this, 'fname', 'submit')" /><br />
 File name: <input type='text' value='' name='denumire' id='fname' /><br />
 <input type='submit' id='submit' value='Submit' disabled='disabled' />
</form>

<script>
var ar_ext = ['pdf', 'gif', 'jpe', 'jpg']; // array with allowed extensions

function checkName(el, to, sbm) {
// - coursesweb.net
 // get the file name and split it to separe the extension
 var name = el.value;
 var ar_name = name.split('.');

 // for IE - separe dir paths (\) from name
 var ar_nm = ar_name[0].split('\\');
 for(var i=0; i<ar_nm.length; i++) var nm = ar_nm[i];

 // add the name in 'to'
 document.getElementById(to).value = nm;

 // check the file extension
 var re = 0;
 for(var i=0; i<ar_ext.length; i++) {
 if(ar_ext[i] == ar_name[1]) {
 re = 1;
 break;
 }
 }

 // if re is 1, the extension is in the allowed list
 if(re==1) {
 // enable submit
 document.getElementById(sbm).disabled = false;
 }
 else {
 // delete the file name, disable Submit, Alert message
 el.value = '';
 document.getElementById(sbm).disabled = true;
 alert('.'+ ar_name[1] +' is not an file type allowed for upload');
 }
}
</script>

upload.php code

<?php
// - coursesweb.net
$updir = 'uploads/'; // sets the folder where the uploaded files are copied
$max_size = 100; // sets maximum file size allowed (in KB)

// file types allowed
$allowtype = array('pdf', 'gif', 'jpg', 'jpe');

// If is received a valid file from the 'fup' form field
if (isset($_FILES['fup'])) {
 // check for errors
 if ($_FILES['fup']['error'] > 0) {
 echo 'Error: '. $_FILES['fup']['error']. '<br />';
 }
 else {
 // get the name, size (in kb) and type (the extension) of the file
 $fname = $_FILES['fup']['name'];
 $fsize = $_FILES['fup']['size'] / 1024;
 $ftype = end(explode('.', strtolower($fname)));

 // checks if the file already exists
 if (file_exists($updir. $fname)) {
 echo 'The file: '. $fname. ' already exists';
 }
 else {
 // if the file not exists, check its type (by extension) and size
 if (in_array($ftype, $allowtype)) {
 // check the size
 if ($fsize <= $max_size) {
 // uses function to copy the file from temporary folder to $updir
 if (!move_uploaded_file ($_FILES['fup']['tmp_name'], $updir. $fname)) {
 echo 'The file '. $fname. ' could not be copied, try again';
 }
 else {
 echo $fname. ' ('. $fsize. ' kb) was successfully uploaded';
 }
 }
 else {
 echo 'The file '. $fname. ' exceeds the maximum permitted size, '. $max_size. ' KB';
 }
 }
 else {
 echo $fname. ' - invalid file type';
 }
 }
 }
}
else echo 'Invalid form data';
?>