ESQ and javascript

. Perform verification whenever a user adds or modifies a daily program. If the total number of active daily programs exceeds the system setting value (see above), saving a record should not be permitted. Instead, a user should receive a message informing that the number of concert halls is limited and no more than “N” daily programs can be active at a time, where “N” is the system setting value. Implementation method: handlers in the JavaScript code of the edit page with applying the client ESQ and validation mechanism.

Could be please suggest steps or code to perform this ?