AJAX Page - Send data back to client

How to send back data

The AJAX Page ASP.NET control allows you to send back a response to the client after the
server-side processing is finished. You have multiple options to do this:

1. Return values from the server-side methods. The data returned by these
methods will be the value that the post function returns on the client-side.
        
        public string onEdit(string sNewValue, string sOldValue)
        {
            // process the information
            // .....
            return sOldValue + " was replaced with " + sNewValue; // response returned to the client
        }
		

2. If you don't want to receive any kind of response from the server when the
processing is finished, then you have to declare the server-side methods as void.
The post function will return an empty string to the client-side.
		
        public void onClick(string sValue)
        {
            // server-side processing
            // .....    
        }
        

3. Another way to send data to the client is to use the server-side ExecBeforeLoad or ExecOnLoad methods.

This methods takes as parameter a javascript command or set of commands that will be executed on the client-side:
  - in case of ExecBeforeLoad, before the post function returns the response from the server.
  - in case of ExecOnLoad, after the post function returns the response from the server.
        
        public string onSubmit(string name, int age)
        {
            int ageAdd = 10;
            ExecBeforeLoad("alert('something')");
            ExecBeforeLoad("customJsFunction(" + ageAdd.ToString() + ")");
            return name + " will be " + (age + ageAdd) + " in " + ageAdd + " years";
        }
	
        public string onSubmit(string name, int age)
        {
            int ageAdd = 10;
            ExecOnLoad("alert('something')");
            ExecOnLoad("customJsFunction(" + ageAdd.ToString() + ")");
            return name + " will be " + (age + ageAdd) + " in " + ageAdd + " years";
        }
        

Both ExecBeforeLoad and ExecOnLoad methods can be used more than once for a specific event.