Error Console: Difference between revisions

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m (tweak the code; add a link to JS coding guidelines)
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You can output information to console using the following method:
You can output information to console using the following method:


<ul>
<ol>
<li>Declare global variable gConsoleService:
<li>Declare a global variable (but be sure to use an [[Dev : Javascript coding guidelines|unique identifier]]!):
<pre>var gConsoleService;</pre>
<pre>var gConsoleService = Components.classes['@mozilla.org/consoleservice;1']
</li>
<li>Initialize it [[Dev : Extensions : onLoad|on load]]:
<pre>gConsoleService = Components.classes['@mozilla.org/consoleservice;1']
                     .getService(Components.interfaces.nsIConsoleService);</pre>
                     .getService(Components.interfaces.nsIConsoleService);</pre>
(note, you can also use toJavaScriptConsole() function to open JavaScript console on startup)
(note, you can also use <tt>toJavaScriptConsole()</tt> function to open JavaScript console on startup)
</li>
</li>
<li>Define a function:
<li>Define a function:
<pre>function MyApp_logMessage(aMessage) {
<pre>function myExt_logMessage(aMessage) {
   gConsoleService.logStringMessage('MyApp: ' + aMessage);
   gConsoleService.logStringMessage('My extension: ' + aMessage);
}</pre>
}</pre>
</li>
</li>
<li>Use it like here:
<li>Use it like here:
<pre>MyApp_logMessage('Initialized.');</pre>
<pre>myExt_logMessage("Initialized.");</pre>
</li>
</li>
</ul>
</ol>


See also: [[Dev : Tips : Enabling dump|Using dump()]], [http://www.mozilla.org/projects/xpcom/using-consoleservice.html Using Console Service].
See also: [[Dev : Tips : Enabling dump|Using dump()]], [http://www.mozilla.org/projects/xpcom/using-consoleservice.html Using Console Service].

Revision as of 10:54, 31 October 2004

You can output information to console using the following method:

  1. Declare a global variable (but be sure to use an unique identifier!):
    var gConsoleService = Components.classes['@mozilla.org/consoleservice;1']
                        .getService(Components.interfaces.nsIConsoleService);

    (note, you can also use toJavaScriptConsole() function to open JavaScript console on startup)

  2. Define a function:
    function myExt_logMessage(aMessage) {
      gConsoleService.logStringMessage('My extension: ' + aMessage);
    }
  3. Use it like here:
    myExt_logMessage("Initialized.");

See also: Using dump(), Using Console Service.