This page describes the JavaScript Debugger as it appears before Firefox 52.
The following are different ways to set a breakpoint within the JavaScript code in the debugger.
- in the source pane, click on the line number for the line you want to break at
- in the source pane, activate the context menu while on the line you want to break at, and select "Add breakpoint"
- in the source pane, highlight the line you want to break at and press Ctrl+B (Windows/Linux) or Command+B (Mac OS X)
Each breakpoint is shown in two places in the debugger:
- they're listed in the source list pane underneath the file's name
- the line in the source pane is marked with a blue arrow, or an orange arrow if the breakpoint is conditional
The screenshot below shows breakpoints at lines 20 and 28 of the file. The breakpoint at line 20 has been hit:
