data-layoutattribute of #mqttchat div is very important, it allows you to specify the layout to load. Currently it only takes the value "embedded" to load the embedded MQTT chat layout or "docked" to load docked layout. Other layouts are under development.
data-layoutattribute when calling MQTT chat cloud is helpfull in case you want to show only notifications for users when they receive new messages or to show not read messages count when they are navigating between different pages of your site. In this case you can call MQTT chat cloud using data-user-id only.
classattribute of #mqttchat div allows you to specify what mqttchat theme to use for a specific layout. Currently it only takes the value "mqttchat-default" to load default theme, "mqttchat-dark" to load dark theme or "mqttchat-lite" to load lite theme. Other themes are under development.
classattribute is absent, the default mqttchat theme is then loaded.
srcto use your locale. For example, you can replace en with your locale, such as fr for french. Currently three languages are supported en, fr and ar.