Because the script debugger is based on Eclipse, there are a number of views available to use with debugger. For more information on these views, consult the Eclipse documentation.
However, there are two views that might be of particular interest.
Variables View
You can use the variables view to view the variables and their values in the stack frame. The Variables view appears by default in the Debug perspective.
Expressions View
You can use the expression view to evaluate expressions in the context of the current stack frame.