jquery validation engine example for file upload allowed extension

1<script>
2  ;(function($) {
3    $('input#submit').click(function() {
4      var file = $('input[type="file"]').val();
5      var exts = ['doc','docx','rtf','odt'];
6      // first check if file field has any value
7      if ( file ) {
8        // split file name at dot
9        var get_ext = file.split('.');
10        // reverse name to check extension
11        get_ext = get_ext.reverse();
12        // check file type is valid as given in 'exts' array
13        if ( $.inArray ( get_ext[0].toLowerCase(), exts ) > -1 ){
14          alert( 'Allowed extension!' );
15        } else {
16          alert( 'Invalid file!' );
17        }
18      }
19    });
20  })(jQuery);
21</script>