added condition for empty ids.

@@ -49,7 +49,12 @@ switch ($action) {
 			$instance->cmid  = $madatorycmids;
 			$instance->cmid  = $madatorycmids;
 			$instance->mandatory  = $mandatoryactivities->mandatory;
 			$instance->mandatory  = $mandatoryactivities->mandatory;
 			
 			
+			if (!empty($madatorycmids)){
 				$DB->update_record('local_mandatory_activities', $instance);
 				$DB->update_record('local_mandatory_activities', $instance);
+			}else{
+				$sql="delete from mdl_local_mandatory_activities where course=$course";
+				$DB->execute($sql);
+			}
 			
 			
 		}else{
 		}else{
 			
 			
@@ -84,7 +89,7 @@ switch ($action) {
 				$allcmids[]=$value->id;
 				$allcmids[]=$value->id;
 		}
 		}
 		
 		
-		if ($mandatoryids && $checkedids){
+		if ($mandatoryids || $checkedids){
 			
 			
 			$previousestatus=explode(",",$mandatoryids);
 			$previousestatus=explode(",",$mandatoryids);
 			foreach($checkedids as $id){
 			foreach($checkedids as $id){
@@ -140,7 +145,41 @@ switch ($action) {
 				$unchangedactivities[]=$aname;
 				$unchangedactivities[]=$aname;
 				}
 				}
 			}
 			}
-		}else{
+		}else if ($checkedids) {
+			
+			foreach($checkedids as $id){
+				
+				if (isset($qresult[$id])){
+					$id=number_format($id);
+					$modaname=$qresult[$id]->name;
+					$instance=$qresult[$id]->instance;
+						
+					$sqlactivityname="select name from mdl_$modaname where id=$instance";
+					$aname=$DB->get_record_sql($sqlactivityname);
+						
+					$newlyaddedactivities[]=$aname;
+					$newlyaddedids[]=$id;
+				}
+			}
+			
+			$res=array_diff($allcmids,$newlyaddedids);
+			$unchangedids=array_diff($res,$removedids);
+				
+			foreach ($unchangedids as $data){
+				if (isset($qresult[$data])){
+					$id=number_format($data);
+					$modaname=$qresult[$data]->name;
+					$instance=$qresult[$data]->instance;
+						
+					$sqlactivityname="select name from mdl_$modaname where id=$instance";
+					$aname=$DB->get_record_sql($sqlactivityname);
+						
+					$unchangedactivities[]=$aname;
+				}
+			}
+			
+		}
+		else{
 			
 			
 			foreach ($qresult as $val){
 			foreach ($qresult as $val){
 				$modaname=$val->name;
 				$modaname=$val->name;

@@ -128,15 +128,20 @@ th,td{
 	
 	
 		$(document).on('click', '#savemandatory', function(){
 		$(document).on('click', '#savemandatory', function(){
 		
 		
-		$('#madatorysection').css("display", "none");
-		$('#loadingcomparision').css("display", "block");
-		
 			var checkedids=[];
 			var checkedids=[];
 			
 			
 			$('input:checkbox.checkboxesavilable:checked').each(function () {
 			$('input:checkbox.checkboxesavilable:checked').each(function () {
        			checkedids.push($(this).attr("data-cmid"));
        			checkedids.push($(this).attr("data-cmid"));
   			});
   			});
   			
   			
+  			
+  //			if(checkedids.length > 0){
+  			
+  				$('#madatorysection').css("display", "none");
+				$('#loadingcomparision').css("display", "block");
+  			
+  			
+	
 			var rootPath = M.cfg.wwwroot;
 			var rootPath = M.cfg.wwwroot;
             var arg = { action:'getcomparision',
             var arg = { action:'getcomparision',
 						checked:checkedids,
 						checked:checkedids,
@@ -221,6 +226,12 @@ th,td{
 				}
 				}
 			});
 			});
 			
 			
+//			}else{
+			
+//			alert("Please do select atleast one activity to proceed");
+			
+//			}
+
 	//	$('#accordion1').css("display", "none");
 	//	$('#accordion1').css("display", "none");
 
 
 	});
 	});
@@ -267,7 +278,7 @@ th,td{
 					
 					
 					$('#loadingcomparision').css("display", "none");
 					$('#loadingcomparision').css("display", "none");
 					
 					
-					var alerttags='<div class="alert alert-success"><strong>Successfully Ssved</strong></div>';
+					var alerttags='<div class="alert alert-success"><strong>Successfully Saved</strong></div>';
 					$('#successalert').append(alerttags);
 					$('#successalert').append(alerttags);
 					
 					
 					 setTimeout(function(){
 					 setTimeout(function(){