Simple log wrapper which prints line numbers...

log.js

window.log = (function (console) {
  'use strict';
  
  var COUNT = 0;
       
  return function () {
    var args = Array.prototype.slice.call(arguments),
        line = [++COUNT + ':'];
    
    if (typeof console === 'object') {
      console.log.apply(console, line.concat(args));
    }
  };
}(console));