Hi,
When we have 2 tables related with one field required, if the user input a value which doesn't exist, he receives a system error message "Error ... occured on the server". I wanted to trap the message and show an alert message where I can write what I want following the circumstances.
The first thing is to know which event is trapped when we input a field in a related field (The event onAfterFind is not fired)
The second thing is to know how to trap the error. I have read that in Javascript we could use the script

window.error = function_error;
function function_error(txtMessage, txtAddress, nbline) { ...}

but it seems not useable for such system error.

Jacques