This method is used in the processing page to trigger a client-side function from the server,
before the processing starts.
After the client-side function is executed, the server-side processing continues.
You can have unlimited number of ExecBeforeLoad methods, and as a parameter
Here is a short example:
public string onClick(int myInt)
// ExecBeforeLoad examples
// return the number received as argument multiplied by 10
return myInt * 10;
See also ExecBeforeLoad example