# log4javascript

# log4javascript 1.4 Lite

## Contents

- Introduction
- Code
- API

## Introduction

log4javascript Lite is designed to be a basic, lightweight, cross-browser logging tool. It provides functions to log messages of different severity to a pop-up window using the exactly the same syntax as log4javascript.

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## Code

You can copy the code for log4javascript Lite below:

if(!Array.prototype.shift){Array.prototype.shift=function(){if(this.length>0){var firstItem=this[0];for(var i=0,len=this.length-1;i<len;i++){this[i]=this[i+1];} this.length--;return firstItem;}};} var log4javascript;(function(){var newLine="\r\n";function Log4JavaScript(){} log4javascript=new Log4JavaScript();log4javascript.version="1.4.13";log4javascript.edition="log4javascript_lite";function getExceptionMessage(ex){if(ex.message){return ex.message;}else if(ex.description){return ex.description;}else{return String(ex);}} function getUrlFileName(url){var lastSlashIndex=Math.max(url.lastIndexOf("/"),url.lastIndexOf("\\"));return url.substr(lastSlashIndex+1);} function getExceptionStringRep(ex){if(ex){var exStr="Exception: "+getExceptionMessage(ex);try{if(ex.lineNumber){exStr+=" on line number "+ex.lineNumber;} if(ex.fileName){exStr+=" in file "+getUrlFileName(ex.fileName);}}catch(localEx){} if(showStackTraces&&ex.stack){exStr+=newLine+"Stack trace:"+newLine+ex.stack;} return exStr;} return null;} function isError(err){return(err instanceof Error);} function bool(obj){return Boolean(obj);} var enabled=(typeof log4javascript_disabled!="undefined")&&log4javascript_disabled?false:true;log4javascript.setEnabled=function(enable){enabled=bool(enable);};log4javascript.isEnabled=function(){return enabled;};var showStackTraces=false;log4javascript.setShowStackTraces=function(show){showStackTraces=bool(show);};var Level=function(level,name){this.level=level;this.name=name;};Level.prototype={toString:function(){return this.name;},equals:function(level){return this.level==level.level;},isGreaterOrEqual:function(level){return this.level>=level.level;}};Level.ALL=new Level(Number.MIN_VALUE,"ALL");Level.TRACE=new Level(10000,"TRACE");Level.DEBUG=new Level(20000,"DEBUG");Level.INFO=new Level(30000,"INFO");Level.WARN=new Level(40000,"WARN");Level.ERROR=new Level(50000,"ERROR");Level.FATAL=new Level(60000,"FATAL");Level.OFF=new Level(Number.MAX_VALUE,"OFF");log4javascript.Level=Level;function Appender(){var getConsoleHtmlLines=function(){return['<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">','<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">','<head>','<title>log4javascript</title>','<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />','<!-- Make IE8 behave like IE7, having gone to all the trouble of making IE work -->','<meta http-equiv="X-UA-Compatible" content="IE=7" />','<script type="text/javascript">','//<![CDATA[','var loggingEnabled=true;var messagesBeforeDocLoaded=[];function toggleLoggingEnabled(){setLoggingEnabled($("enableLogging").checked);}','function setLoggingEnabled(enable){loggingEnabled=enable;}','function scrollToLatestEntry(){var l=getLogContainer();if(typeof l.scrollTop!="undefined"){var latestLogEntry=l.lastChild;if(latestLogEntry){l.scrollTop=l.scrollHeight;}}}','function log(logLevel,formattedMessage){if(loggingEnabled){if(loaded){doLog(logLevel,formattedMessage);}else{messagesBeforeDocLoaded.push([logLevel,formattedMessage]);}}}','function doLog(logLevel,formattedMessage){var logEntry=document.createElement("div");logEntry.appendChild(document.createTextNode(formattedMessage));logEntry.className="logentry "+logLevel.name;getLogContainer().appendChild(logEntry);scrollToLatestEntry();}','function mainPageReloaded(){var separator=document.createElement("div");separator.className="separator";separator.innerHTML=" ";getLogContainer().appendChild(separator);}','var loaded=false;var logLevels=["DEBUG","INFO","WARN","ERROR","FATAL"];window.onload=function(){setLogContainerHeight();toggleLoggingEnabled();for(var i=0;i<messagesBeforeDocLoaded.length;i++){doLog(messagesBeforeDocLoaded[i][0],messagesBeforeDocLoaded[i][1]);}','messagesBeforeDocLoaded=[];loaded=true;setTimeout(setLogContainerHeight,20);};function getLogContainer(){return $("log");}','function clearLog(){getLogContainer().innerHTML="";}','function $(id){return document.getElementById(id);}','function getWindowHeight(){if(window.innerHeight){return window.innerHeight;}else if(document.documentElement&&document.documentElement.clientHeight){return document.documentElement.clientHeight;}else if(document.body){return document.body.clientHeight;}','return 0;}','function getChromeHeight(){return $("toolbar").offsetHeight;}','function setLogContainerHeight(){var windowHeight=getWindowHeight();$("body").style.height=getWindowHeight()+"px";getLogContainer().style.height=""+','Math.max(0,windowHeight-getChromeHeight())+"px";}','window.onresize=function(){setLogContainerHeight();};','//]]>','</scr' + 'ipt>','<style type="text/css">','body{background-color:white;color:black;padding:0;margin:0;font-family:tahoma,verdana,arial,helvetica,sans-serif;overflow:hidden}div#toolbar{border-top:solid #ffffff 1px;border-bottom:solid #aca899 1px;background-color:#f1efe7;padding:3px 5px;font-size:68.75%}div#toolbar input.button{padding:0 5px;font-size:100%}div#log{font-family:Courier New,Courier;font-size:75%;width:100%;overflow:auto;clear:both}*.logentry{overflow:visible;white-space:pre}*.TRACE{color:#666666}*.DEBUG{color:green}*.INFO{color:#000099}*.WARN{color:#999900}*.ERROR{color:red}*.FATAL{color:#660066}div#log div.separator{background-color:#cccccc;margin:5px 0;line-height:1px}','</style>','</head>','<body id="body">','<div id="toolbar">','Options:','<input type="checkbox" id="enableLogging" onclick="toggleLoggingEnabled()" class="stateful" checked="checked" title="Enable/disable logging" /><label for="enableLogging" id="enableLoggingLabel">Enable logging</label>','<input type="button" id="clearButton" value="Clear" onclick="clearLog()" class="stateful button" title="Clear all log messages" />','<input type="button" id="closeButton" value="Close" onclick="window.close()" class="stateful button" title="Close the window" />','</div>','<div id="log" class="TRACE DEBUG INFO WARN ERROR FATAL"></div>','</body>','</html>'];};var popUp=null;var popUpsBlocked=false;var popUpClosed=false;var popUpLoaded=false;var complainAboutPopUpBlocking=true;var initialized=false;var isSupported=true;var width=600;var height=400;var focusPopUp=false;var queuedLoggingEvents=new Array();function isLoaded(win){try{return bool(win.loaded);}catch(ex){return false;}} function finalInit(){popUpLoaded=true;appendQueuedLoggingEvents();} function writeHtml(doc){var lines=getConsoleHtmlLines();doc.open();for(var i=0,len=lines.length;i<len;i++){doc.writeln(lines[i]);} doc.close();} function pollConsoleWindow(){function pollConsoleWindowLoaded(){if(popUpLoaded){clearInterval(poll);}else if(bool(popUp)&&isLoaded(popUp)){clearInterval(poll);finalInit();}} var poll=setInterval(pollConsoleWindowLoaded,100);} function init(){var windowProperties="width="+width+",height="+height+",status,resizable";var windowName="log4javascriptLitePopUp"+location.host.replace(/[^a-z0-9]/gi,"_");popUp=window.open("",windowName,windowProperties);popUpClosed=false;if(popUp){if(isLoaded(popUp)){popUp.mainPageReloaded();finalInit();}else{writeHtml(popUp.document);if(isLoaded(popUp)){finalInit();}else{pollConsoleWindow();}}}else{isSupported=false;if(complainAboutPopUpBlocking){alert("log4javascript: pop-up windows appear to be blocked. Please unblock them to use pop-up logging.");}} initialized=true;} function safeToAppend(){if(!popUpsBlocked&&!popUpClosed){if(popUp.closed){popUpClosed=true;return false;} if(!popUpLoaded&&popUp.loaded){popUpLoaded=true;}} return!popUpsBlocked&&popUpLoaded&&!popUpClosed;} function padWithZeroes(num,len){var str=""+num;while(str.length<len){str="0"+str;} return str;} function padWithSpaces(str,len){while(str.length<len){str+=" ";} return str;} this.append=function(loggingEvent){if(!initialized){init();} queuedLoggingEvents.push(loggingEvent);if(safeToAppend()){appendQueuedLoggingEvents();}};function appendQueuedLoggingEvents(){if(safeToAppend()){while(queuedLoggingEvents.length>0){var currentLoggingEvent=queuedLoggingEvents.shift();var date=currentLoggingEvent.timeStamp;var formattedDate=padWithZeroes(date.getHours(),2)+":"+ padWithZeroes(date.getMinutes(),2)+":"+padWithZeroes(date.getSeconds(),2);var formattedMessage=formattedDate+" "+padWithSpaces(currentLoggingEvent.level.name,5)+" - "+currentLoggingEvent.getCombinedMessages();var throwableStringRep=currentLoggingEvent.getThrowableStrRep();if(throwableStringRep){formattedMessage+=newLine+throwableStringRep;} popUp.log(currentLoggingEvent.level,formattedMessage);} if(focusPopUp){popUp.focus();}}}} log4javascript.Appender=Appender;function Logger(){var appender=new Appender();var loggerLevel=Level.ALL;this.log=function(level,params){if(enabled&&level.isGreaterOrEqual(this.getLevel())){var exception;var finalParamIndex=params.length-1;var lastParam=params[params.length-1];if(params.length>1&&isError(lastParam)){exception=lastParam;finalParamIndex--;} var messages=[];for(var i=0;i<=finalParamIndex;i++){messages[i]=params[i];} var loggingEvent=new LoggingEvent(this,new Date(),level,messages,exception);appender.append(loggingEvent);}};this.setLevel=function(level){loggerLevel=level;};this.getLevel=function(){return loggerLevel;};} Logger.prototype={trace:function(){this.log(Level.TRACE,arguments);},debug:function(){this.log(Level.DEBUG,arguments);},info:function(){this.log(Level.INFO,arguments);},warn:function(){this.log(Level.WARN,arguments);},error:function(){this.log(Level.ERROR,arguments);},fatal:function(){this.log(Level.FATAL,arguments);},isEnabledFor:function(level){return level.isGreaterOrEqual(this.getLevel());},isTraceEnabled:function(){return this.isEnabledFor(Level.TRACE);},isDebugEnabled:function(){return this.isEnabledFor(Level.DEBUG);},isInfoEnabled:function(){return this.isEnabledFor(Level.INFO);},isWarnEnabled:function(){return this.isEnabledFor(Level.WARN);},isErrorEnabled:function(){return this.isEnabledFor(Level.ERROR);},isFatalEnabled:function(){return this.isEnabledFor(Level.FATAL);}};var defaultLogger=null;log4javascript.getDefaultLogger=function(){if(!defaultLogger){defaultLogger=new Logger();} return defaultLogger;};log4javascript.getLogger=log4javascript.getDefaultLogger;var nullLogger=null;log4javascript.getNullLogger=function(){if(!nullLogger){nullLogger=new Logger();nullLogger.setLevel(Level.OFF);} return nullLogger;};var LoggingEvent=function(logger,timeStamp,level,messages,exception){this.logger=logger;this.timeStamp=timeStamp;this.level=level;this.messages=messages;this.exception=exception;};LoggingEvent.prototype={getThrowableStrRep:function(){return this.exception?getExceptionStringRep(this.exception):"";},getCombinedMessages:function(){return(this.messages.length===1)?this.messages[0]:this.messages.join(newLine);}};log4javascript.LoggingEvent=LoggingEvent;window.log4javascript=log4javascript;})();

Press this button to copy the code to the clipboard:

You can either paste the above code inside a script tag:

    <script type="text/javascript">
    	... [Code here]...
    </script>

... or include the `log4javascript_lite.js` included in the distribution:

    <script type="text/javascript" src="log4javascript_lite.js"></script>

    <script type="text/javascript">
    	var log = log4javascript.getDefaultLogger();
    </script>

Using log4javascript Lite is identical to using log4javascript with its default logger:

    <script type="text/javascript">
    	var log = log4javascript.getDefaultLogger();
    	log.debug("What's going on here then?");
    </script>

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## API

The functions available in log4javascript Lite make up a small subset of those provided by log4javascript proper. Each function is named and called identically to the equivalent function in log4javascript. Full details can be found in the log4javascript Lite manual.

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