var xmlhttp

function closeComments(){
    document.getElementById("c_errmsg").style.display = "none";
    tb_remove();
}

function loadXMLDoc()
{
    
    var a = document.getElementById("Author").value;
    var c = document.getElementById("Comment").value;

    if (a==""||c==""){
            document.getElementById("c_errmsg").style.display = "block";
        }else{
        
            var url = "comment_add.asp?author=" + a + "&comment=" + c;
            
            xmlhttp=null
            // code for Mozilla, etc.
            if (window.XMLHttpRequest)
              {
              xmlhttp=new XMLHttpRequest()
              }
            // code for IE
            else if (window.ActiveXObject)
              {
              xmlhttp=new ActiveXObject("Microsoft.XMLHTTP")
              }
            if (xmlhttp!=null)
              {

              xmlhttp.onreadystatechange=state_Change
              xmlhttp.open("GET",url,true)
              xmlhttp.send(null)
              }
            else
              {
              alert("Your browser does not support XMLHTTP.")
              }
          }
}

function state_Change()
{
// if xmlhttp shows "loaded"
if (xmlhttp.readyState==4)
  {
  // if "OK"
  if (xmlhttp.status==200)
  {
  closeComments();
  }
  else
  {
  alert("Problem retrieving data:" + xmlhttp.statusText)
  }
  }
}