has File Extension

hasExtension

/**
 * Helper function to check file extension for <input type="file"> element.
 * @param  Array     exts  An array containing extension to check. eg. ['.png', '.zip'].
 * @return Boolean         returns ture only if all files are matched given extension otherwise returns false.
 */

$.fn.hasExtension = function(exts) {
  var file_list = this[0].files;
  for (var i = 0, file; file = file_list[i]; i++) {
    var fileName = file.name;
    var result = new RegExp('(' + exts.join('|').replace(/\./g, '\\.') + ')$').test(fileName);
    if (!result) {
      alert('Error: Invalid file extension: ' + fileName);
      return false;
    }
    return true;
  }
}