See Setting up extension development environment#Development preferences for the preferences you should set if you want to see errors from Firefox and extensions in the Error console. For example, your flyout menus may be broken, your metaboxes don't drag, or your add media buttons aren't working. Since the timestamp of each message is different, each message is displayed on its own line. Working with the Console history Clearing the history You can clear the console history by doing any of the following: Right-click in the Console and press Clear console. get redirected here
There may also be large incompatibilities between implementations and the behavior may change in the future. We are happy to help, but will need some additional information. Go to Tools > Web Developer > Error Console. The image to the right shows the error on line 33.
You can use this information when you are making a support request. You'll usually see the context set to top (the top frame of the page). The image above shows the error to be in jquery.js on line 2, however remember to copy the whole stack information! If no debugging is available, the debugger statement has no effect.
Setting & Description Hide network messages By default, the console reports network issues. Message stacking If a message is consecutively repeated, rather than printing out each instance of the message on a new line, the Console "stacks" the messages and shows a number in Stack redundant messages, or display them on their own lines. To find the error location, expand one of the errors.
Message very similar to warning, used very rarely. subst1 ...