anchor.diff:  			opCombo.options[4] = new Option("<%=Operator.GREATER_THAN%>","<%=Operator.GREATER_THAN%>");
   			opCombo.options[5] = new Option("<%=Operator.GREATER_THAN_OR_EQUALS%>","<%=Operator.GREATER_THAN_OR_EQUALS%>");
   		}
  -	}
  -}
  +
  +		opCombo.options[opCombo.options.length] = new Option("<%=Operator.IS_NULL%>","<%=Operator.IS_NULL%>");
  +		opCombo.options[opCombo.options.length] = new Option("<%=Operator.IS_NOT_NULL%>","<%=Operator.IS_NOT_NULL%>");
  +	}
  +}
  +
  +function showDatafield(element,txtFieldID)
  +{
  +	var dataStr = element.options[element.selectedIndex].value;
  +	var dataValue = new String(dataStr);
  +	var txtField = document.getElementById(txtFieldID);
  +	
  +	if(dataValue == "<%=Operator.IS_NULL%>" || dataValue == "<%=Operator.IS_NOT_NULL%>")
  +	{
  +		txtField.disabled = true;
  +	}
  +	else
  +	{
  +		txtField.disabled = false;
  +	}
  +}
  +
   
   </script>
   
  
positive.code: 						String functionName = "showDateColumn(this,'"+ attributeValueID +"','" + columnID + "','" + showCalendarValue + "','"+fieldName+"','"+overDiv+"')";
  						String attributeId = "attribute" + i;
  						String operatorId = "operator" + i;
  						String onAttributeChange = "onAttributeChange(this,'" + operatorId + "'); " + functionName;
  						
  				%>					
  				<tr>
  					<td class="formRequiredNotice" width="5">&nbsp;</td>
  
negative.code: 	}	
  }
  
  function onAttributeChange(element,opComboName,txtFieldID)
  {
  	var columnValue = element.options[element.selectedIndex].value;
  	var index = columnValue.lastIndexOf(".");
  