JS strip_tags

function strip_tags(input, allowed) {
  allowed = (((allowed || '') + '')
    .toLowerCase()
    .match(/<[a-z][a-z0-9]*>/g) || [])
    .join(''); // making sure the allowed arg is a string containing only tags in lowercase (<a><b><c>)
  var tags = /<\/?([a-z][a-z0-9]*)\b[^>]*>/gi,
    commentsAndPhpTags = /<!--[\s\S]*?-->|<\?(?:php)?[\s\S]*?\?>/gi;
  return input.replace(commentsAndPhpTags, '')
    .replace(tags, function($0, $1) {
      return allowed.indexOf('<' + $1.toLowerCase() + '>') > -1 ? $0 : '';
    });
}