fvlogger
all
debug
info
warn
error
fatal
erase

Scatter debug messages throughout your code to provide a high-level overview of what your code is doing, such as which function is currently in scope and the values of loop counters.

Information messages are the meat and potatoes of logging messages; sprinkle them around to reveal more detailed information about your script's execution, such as the values of variables and function/method return values.

Warning messages are used to indicate potentially hazardous situations, such as missing function arguments...

While error messages are used to indicate that something bad is about to happen; note that these kinds of errors are considered to be run-time errors, which are a different type of beast from the parse errors mentioned below.

Error on line 157 of document https://zanstra.com/arc/xs4all/dzLib/fvlogger/logger.js: Uncaught ReferenceError: a is not defined

Javascript variable inspection

string

var s='hoi';
s 'hoi' (string)

number (integer)

var n=12;
n 12 (number, int)

number (float)

var n=12.123;
n 12.123 (number, float)

boolean

var b=true;
b true (boolean)

undefined

var u;
u not initialized (undefined)

null

var N=null;
N null (Object)

Date

var dt=new Date(2005,11-1,17,23,31,45,100);
dt 2005-11-17T23:31:45.100 (Date)

anonymous function

var f=function() { alert('hoi') };
f anonymous (function)

named function

var f=function doei() { alert('hoi') };
f doei (function)

regular expression

var r=/[0-9]{4} ?[a-z]{2}/i;
r /[0-9]{4} ?[a-z]{2}/i (RegExp)

array

var a="A,B,C".split(",");
a: (Array)
  1. length 3 (number)
  2. 0 "A" (string)
  3. 1 "B" (string)
  4. 2 "C" (string)

Anonymous Object

var o={name:'Doekman',email:'doeke@zanstra.net'};
o: (Object)

Named Object

var o=new Person('Doekman','doeke@zanstra.net');
o (Person)