// Options object as parameter 
form.addPageInitMessage({type: message.Type.INFORMATION, message: 'Hello world!', duration: 5000}); 

// Message object as parameter 
var messageObj = message.create({type: message.Type.INFORMATION, message: 'Hello world!', duration: 5000}); form.addPageInitMessage({message: messageObj}); 

// Show message when the record is in view mode
function beforeLoad(context) {
    if(context.type === 'view')
        context.form.addPageInitMessage(messageOptions);
}
...
//Add additional code