A widget is a superset of an Angular directive that is tightly coupled to a server-side JavaScript code block powered by the Rhino engine under the ServiceNow platform.
Since widgets are read-only to benefit from future updates, you can't update their code. If you need to make major changes,
clone the widget and give it another name and id.
Once you drop a widget into a column using the Service Portal Designer it will create a widget instance. A widget instace is a reference to a widget that contains: location, properties and CSS especific for that instance. A widget used multiple times in the same page, will use multiple instances.
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