Bollinger Bands Width Donchian

This script was written for release to my followers in tandem with a video idea on how to use it.

The script draws a line on a lower chart to display the Bollinger Bands Width. The default bars counted for this is 20.

The script then draws and upper and lower Donchian line that moves with the highest high and lowest low of Bollinger Bands Width. The default value of this Donchian is 200. When the Bollinger Bands Width line makes a new Donchian low it highlights the bars for visual recognition.

I have also added alert functionality that can be set to alert when a new low is made.

版本注释:

• Fixed bug with alert functionality.
  
• Added a different background color option (default: red) for the first bar of the Contraction that will trigger the alert.