function CheckTag()
         {
         var U = document.getElementById('username');
         var p = 'username='+U.value+'';
         var opt = {
          method: 'post',
          postBody: p,
          onSuccess: function(t) {
          document.getElementById('CHMESSAGE').innerHTML=(t.responseText>0)?'Available':' <h5>Not Available</h5> ';
          if(t.responseText==0){document.getElementById('username').value='';}
          },
          on404: function(t) {alert('Error 404: location "' + t.statusText + '" was not found.');},
          onFailure: function(t) {alert('Error ' + t.status + ' -- ' + t.statusText);}
          }
          new Ajax.Request('/register/index.html/CHECK_U/nohead', opt);
         }