In thinkScript®, you have the ability to create local alerts. In general, alerts are signals that are triggered when a condition is satisfied.
The common syntax for thinkScript® alerts is the following:
alert(condition, text, alert type, sound);
The condition parameter defines a condition upon which you want this alert to be triggered. The text parameter places a specified text next to the alert. The alert type parameter defines a type of the alert.
Available alert type values are:
- 
Alert.ONCE– alert can be triggered only once after adding a study.
- 
Alert.BAR– alert can be triggered only once per bar.
- 
Alert.TICK– alert can be triggered after each tick
The sound parameter plays a sound when the alert is triggered.
Valid sound values are:
- 
Sound.Bell
- 
Sound.Chimes
- 
Sound.Ding
- 
Sound.NoSound
- 
Sound.Ring
Consider the following script:
Alert(open > 400, "Open is greater than 400! Current value is" + open, alert.ONCE, Sound.Ring);
This example script triggers an alert when the Open price becomes higher than 400. The alert is triggered once and it plays the ring sound.