Log4js

Log4js

File:Log4js.png Log4js Logo
Developer(s)	Stephan Strittmatter, Seth Chisamore
Stable release	1.0 / August 4, 2008
Operating system	Windows, Linux, Mac OS
Type	Framework
License	Apache Software Foundation
Website	http://log4js.berlios.de

Log4js is a framework written in JavaScript to log application events.

The framework is very close to the API of Log4j. It is also available under the licence of Apache Software Foundation.

Functionality

File:Log4JS-UML.jpg

class diagram

The base concept is identical to Log4j. The same log levels and almost all methods are identical.

One special feature of Log4js is the ability to log the events of the browser remote on the server. Using Ajax it is possible to send the logging events in several formats (XML, JSON, plain ASCII etc.) to the server to be evaluated there.

Appender

Following appenders are implemented currently:

AjaxAppender

Sends the logs via XmlHttpRequest (Ajax) to the server to be processed there.

ConsoleAppender

Logs within the HTML page or in a separate window.

FileAppender

Writes to a local file (Internet Explorer and Mozilla supported).

JSConsoleAppender

Appender for the JavaScript Console of Mozilla, Opera and Safari.

MetatagAppender

Adds the log events to Metatags in the DOM of document.

WindowsEventsAppender

Using Internet Explorer it is possible to log to Windows System Events.

Layout

The Layout classes are for different formattings of the events:

BasicLayout

Simple textual output of the events.

HtmlLayout

Formats the event as HTML <div>-element.

JSONLayout

Converts the events to JSON-objects which are readable in many other programming languages like Perl, PHP and Java.

XMLLayout

XML formatted output.

External links

• Log4js Homepage
• Log4js Wiki
• Apache Logging Homepage