Unlimited arguments

example.js

// Antipattern:

var preload = function (path) {
  var img = new Image();
  img.src = path;
};

preload('apple.png');
preload('banana.png');
preload('cheese.png');
preload('donut.png');
preload('egg.png');
preload('fish.png');

// Good pattern:
var preload = function () {
  var args = Array.prototype.slice.call(arguments),
    img;

  for (var i = 0; i < args.length; i++) {
    img = new Image();
    img.src = args[i];
  }
};

preload('apple.png', 'banana.png', 'cheese.png', 'donut.png', 'egg.png', 'fish.png');

// Alternate pattern:

var preload = function () {
  var args = Array.prototype.slice.call(arguments),
    img;

  for (var i = 0; i < args.length; i++) {
    img = new Image();
    img.src = args[i];
  }
};

var args = [ 'apple.png', 'banana.png', 'cheese.png', 'donut.png', 'egg.png', 'fish.png' ];

preload.apply(args);

You can omit the slice.call - arguments has a length and can be iterated like an array (only without its methods). Since the Image Object is not needed furthermore, you can use it anonymously:

var preload = function(){
  for (var i = 0, l = arguments.length; i < l; i++) {
     (new Image()).src = arguments[i];
  }
};