To start script debugging put at least one breakpoint and execute the Debug » Debug Script command.
Placing Breakpoints
To place a breakpoint use a mouse (click on the leftmost area next to a line you want to put breakpoint on) or move the cursor to the line and execute the Debug » Toggle Breakpoint command.
Other commands in the Debug menu allow you to remove all breakpoints or to break a running script asynchronously.
Whenever a breakpoint is hit, script execution enters the break state.
Break State
While in break state, Debug Watch Tool Window and Debug Stack Trace Tool Window display the current execution state. Debug Watch window automatically shows you all local and global variables and allows entering new variable names or expressions to execute and display. Debug Stack Trace window shows you the current stack frame and all calling frames. You can switch to any frame by double-clicking it in the list to change the context of the Debug Watch window.
Stepping through the Code
While in break state, use the following commands to step through the code:
Step In
This command executes the current statement and then enters the break state again. If the current statement is a function call, execution “enters” the function and stops at the function beginning.
Step Over
This command executes the current statement and then enters the break state again. If the current statement is a function call, the function body is executed and execution stops again when the function returns.
Step Out
Continues execution until the currently executed function returns to its caller.
Continue
Continues the execution until the next breakpoint is hit or script execution finishes.