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Updated: how to use this feature from the command line

This Firebug feature is called simply Log Events and allows developers to log DOM events into the Console panel.

All you need to do is right click on an element in the HTML panel, pick Log Events from the context menu and switch to the Console panel to see the logs in action.

Logs in the Console Panel

If you activate logging e.g. for the body element and move your mouse cursor over the page, you should immediately see mouse related events in the Console panel.

Learn & Discover Events

This feature can be also used to learn & discover existing events. Let's try to log events for an input element.

Test input element (install Firebug and check it out right now):

The sequence of events displayed on the screenshot above corresponds to the following actions:

  1. focus: tab key pressed to set focus on the input
  2. select
  3. keyup: tab key released (keyCode=9)
  4. keydown: a key pressed (keyCode=65)
  5. keypress a character pressed (charCode=97)
  6. input Value of the input field has been changed
  7. keyup: a key released (keyCode=65)
  8. keydown: tab key pressed (keyCode=9)
  9. keypress (yet for the tab key pressed)
  10. change
  11. blur: Focus lost
  12. keyup: tab key released (keyCode=9)

Check out DOM event reference

Event Details

Inspecting the event object (associated with an event) is also possible. Just click on the green event label and Firebug automatically selects the DOM tab with event details.

Command Line

Event logging for an element can be also activated through Firebug Command Line. There are two related commands.

  • monitorEvents(object[, types])
  • unmonitorEvents(object[, types])

Let's see some examples.

Instead of right clicking on the body element to activate/deactivate the logging (see the first screenshot) you can type and execute following expressions into the command line. All events, just like before, will be logged in the Console panel.

monitorEvents(document.body);
unmonitorEvents(document.body);

If you want to log only specific events and avoid e.g. mousemove events check out the next example.

var myInput = document.getElementById("myInput");
monitorEvents(myInput, ["keyup", "keydown", "keypress"]);

This way, only keyup, keydown and keypress events will be logged into the Console panel for the test input box available above (in the Learn & Discover Events section). You can open Firebug on this page and check it out immediately.

See also Firebug wiki for monitorEvents and unmonitorEvents API.

 


If you have any tips how to improve this feature let us know.


Rss Commenti

10 Comments

  1. Honza, you should also mention monitorEvents()/unmonitorEvents(), which give more granular control over event logging.

    Sebastian

    #1 Sebastian Z.
  2. Can you play back these events for automated testing type scenarios?

    #2 DDD
  3. @Sebastian Z.: yep good point.

    #3 Honza
  4. @DDD: Not now, but sounds like a good idea. Perhaps new Firebug extension could implement that?

    #4 Honza
  5. [...] logs (see more about DOM event logging) are automatically linked with the target (issue [...]

    #5 Getfirebug Blog » Blog Archive » Firebug 1.11 alpha 1
  6. How can I enable event logging as soon as the document starts loading? I'm interested in logging all events sent to the "window.document" object right from the start, including any readystatechange and the DOMContentLoaded event.

    #6 Sergiu Dumitriu
  7. @Sergiu Dumitriu: Good point, I don't think it's currently possible, please create a new issue report http://code.google.com/p/fbug/issues/list

    Honza

    #7 Honza
  8. @Sergiu: I just did that report so, it isn't forgotten. http://code.google.com/p/fbug/issues/detail?id=5861

    Honza

    #8 Honza
  9. Thanks Jan, I've starred the issue.

    #9 Sergiu Dumitriu
  10. Firebug is the awesome tool for developer and code hacker because mostly we are in trouble while adding code in source file and sometime code doesn't properly work then firebug will help you out.

    #10 iPhone Application Developer

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