Is it possible to create some custom JS script to make notification?

So I have this dashboard

what I want if it possible of course is that if the temperature is equal to 30 a JS script is automatically executed a script like

  alert("the temperature exceeded 28");

Is that possible ?
if yes how can we do that

Welcome to the forum.

Do you want the alert message to be somewhere inside the gauge on the screen? If yes, then you can accomplish this in a roundabout way, such as: