function URLMatchClick() {
  var re = new RegExp("http:\/\/");
  var re2 = new RegExp("url");
  
  var comments = document.getElementById("comments").value;
  
  if (comments.match(re) || comments.match(re2)) {
       alert("You cannot use a web address on this page.")
       return false;
  } else {
        return true;
 
  }
  return false;
}