The JavaScript Mark Occurrences feature allows you to see where a variable, method or type is referenced within a JavaScript file.
To use Mark Occurrences:
Stand on a variable, method or type in your file.
All instances where the element is referenced within the file will be highlighted.
To configure Mark Occurrences settings:
The appearance of marked occurrences can be configured in the Annotations preferences page (Window | Preferences | General | Editors | Text Editors | Annotations).