anchor.diff:  			//--for metastatic diseases button 
   			Element.observe('metastatic-diseases-btn', 'click', function(e){
   				var inField = $('metastaticDiseaseSite');
  -				if(inField.value == '') return;
  +				if(inField.value == '') {
  +                    alert('Select a value first.');
  +                    return
  +                };
   			 	this.addDetails('metastaticDiseaseSite', e.element(), inField.value, 'anchorMetastaticDiseases');
   
   			 	//clear the fields
  
positive.code: 		<table class="tablecontent" width="80%">
  			<tr>
  				<td width="90%">
  					<ui:text path="concomitantMedication" size="50"/>
  				</td>
  				<td width="10%">
  					<input id="concomitantMedication-btn" type="button" value="Add"/>
  				</td>
  			</tr>
  			<tr>
  
negative.code: 							}
  						</jsp:attribute>
  					</ui:autocompleter>
                      &nbsp;
                      <input id="metastatic-diseases-btn" type="button" value="Add"/>
                  </td>
  				<td></td>
  			</tr>
  			<tr>
  				<td colspan="2">
  