Debug JavaScript in Chrome
Professional feature: download PyCharm Professional to try.
note
Debugging of JavaScript code is only supported in Google Chrome and in other Chromium-based browsers.
Debug an application that is running on the built-in server
tip
By default, a debugging session starts in a new window with a custom Chrome user data. To open a new Chrome instance with your familiar look-and-feel, configure Chrome in PyCharm to start with your user data, see Starting a debugging session with your default Chrome user data for details.
Example
To restart the new run/debug configuration, click the Debug button (
) in the upper right-hand corner of the PyCharm window or select from the main menu.
Reload the current page in browser
Besides restarting your application by clicking the Rerun button (
) in the Debug tool window, you can also click the Reload in Browser button (
) to reload the page where you have currently navigated. This works the same way as the Reload Page functionality (Ctrl+R) in Chrome.
During a debugging session, clicking the Rerun button () would reload the home.html page with the Submit button. Clicking the Reload in Browser button () reloads the calculator.html page so all the previous script output is cleared and the debugger returns to line 1 in Calculator.js.
Debug an application that is running on the localhost in the development mode
Debug an application that is running on an external web server
Set the breakpoints in the JavaScript code, as required.
Run the application in the development mode. Often you need to run
npm startfor that.When the development server is ready, copy the URL address at which the application is running in the browser - you will need to specify this URL address in the run/debug configuration.
Create a debug configuration of the type JavaScript Debug: from the main menu, select , in the Edit Configurations dialog that opens, click the Add button (
) on the toolbar and select JavaScript Debug from the list. In the Run/Debug Configuration: JavaScript Debug dialog that opens, specify the URL address at which the application is running. This URL can be copied from the address bar of your browser as described in Step 2 above. Click OK to save the configuration settings.Select the newly created configuration from the Select run/debug configuration list on the toolbar and click the Run button (
) next to the list. The URL address specified in the run configuration opens in the browser and the Debug tool window appears.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, run JavaScript code snippets in the Console, and so on. .
Debug asynchronous code
Debug workers
Set the breakpoints in the Workers to debug.
If you are using Service Workers, make sure the Allow unsigned requests checkbox is selected on the Debugger page (). Otherwise your service workers may be unavailable during a debug session.
Create a debug configuration of the type JavaScript Debug as described above in Debugging client-side JavaScript running on an external web server.
Select the newly created configuration from the Select run/debug configuration list on the toolbar and click the Debug button (
) next to the list. The HTML file specified in the run configuration opens in the browser and the Debug tool window opens with the Frames list showing all the Workers:
To examine the data (variables, watches, and so on) for a Worker, select its thread in the list and view its data in the Variables and Watches panes. When you select another Worker, the contents of the panes are updated accordingly.
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