Debugging JavaScript in Firefox
With WebStorm, you can debug your client-side JavaScript in Firefox, version 36 and higher, using the Firefox remote debugging functionality. However it is strongly recommended that you use Chrome or any other browser of the Chrome family.
On this page:
Enabling debugging in Firefox
With WebStorm, you can debug your client-side JavaScript in Firefox, version 36 and higher, using the Firefox remote debugging functionality.
To enable Firefox remote debugging
- Open your Firefox browser, then open .
- In the Development Tools pane that opens, click Toolbox Options button on the toolbar and select the Enable remote debugging check box under Advanced Settings.
- Choose
listen <port number>
. You can set any port number, however it is recommended that you use 6000 and higher. Later you will specify this port number in the run configuration. . In the console that opens at the bottom of the browser, type
Debugging an application
You can debug an application running on the WebStorm built-in web server on an external server.
To start debugging
- Set the breakpoints in the JavaScript code, as required.
- Create a debug configuration of the type Firefox Remote:
Choose on the main menu, click the Add New Configuration button on the toolbar, and select Firefox Remote from the pop-up list. - In the Run/Debug Configuration: Firefox Remote dialog box that opens, type
localhost
in the Host field. In the Port field, type the port that you specified when you enabled remote debugging in Firefox. The default value is6000
. - Open your application in Firefox. The browser shows the application after the code execution, that is, the breakpoints you set have no effect yet.
- Choose the newly created configuration in the Select run/debug configuration drop-down list on the toolbar and click the Debug toolbar button .
- In the dialog box that opens, click OK to allow incoming connection from the browser.
- Refresh the application page in the browser: the page shows the results of code execution up to the first breakpoint.
- In the Debug tool window, proceed as usual: step through the program, stop and resume the program execution, examine it when suspended, view actual HTML DOM, etc.
Example
Suppose you have a simple application that consists of two files: index.html
and index.js
file, where index.html
references index.js
. This example shows how you can debug the application when it is running on the WebStorm built-in server.
To start debugging
- Set the breakpoints in
index.js
. - Create a FireFox Remote debug configuration, type
localhost
and6000
in the Host and Port fields respectively: - Open
index.html
in the editor, choose Open in browser on the context menu, and then choose Firefox from the list: The browser opens showing the application running on the WebStorm port (currently63345
): - Select the index_firefox_remote configuration from the drop-down list on the toolbar and click the Debug toolbar button : Click OK in the Incoming Connection dialog box that opens: Refresh the application page in the browser.