Stop JavaScript code running when C# validation failed

Question

Hello

 

I am trying to stop the JavaScript code to run when the data is found in the table

 

(dt.Rows.Count > 0). At the moment the code is not inserting data in the database (that what

 

I want) but the JavaScript continues running because I am still getting the successful insert

 

message.Please see de code attached

 

 Thanks for your help

 

Eric