function clearField(fieldId){
   var field = document.getElementById(fieldId);
   var numChars = field.value.length;
   if(numChars != 0){
      var stringNew = field.value.substr(0,numChars-1);
      field.value = stringNew;
      delay(fieldId);
   }
}
function setField(fieldId, originalValue){
   var field = document.getElementById(fieldId);
   if(field.value == ""){
      field.value = originalValue;
   }
}
function delay(fieldId){
   if(fieldId != undefined){
      setTimeout('clearField("'+fieldId+'")', 30);
   }
}