In some instances, it is necessary to obtain server information on the client. The CustomJSProperties event enables you to declare temporary client properties. Once declared, a property can be accessed on the client.
To add new properties, use the event parameter's CustomJSPropertiesEventArgs.Properties property, which represents a collection of property names and their values. The only requirement is that property names must begin with the 'cp' prefix, to avoid rewriting the ASPxRichEdit's base properties.
Typically, using a specifically introduced ASPxRichEdit.JSProperties property might be more convenient and efficient than handling the CustomJSProperties event, which is mostly declared for backward compatibility.