/* This script and many more are available free online at
The JavaScript Source :: <http://javascript.internet.com/>
Created by: Scragar ::
Licensed under: Public Domain */

function BannerRotator(){
// first, defaults:
this.timer = 2;
this.bannerNum = 0;// -1 = random
// then normal init work
this.banners = [];
this.binding = null;
this.timeout = null;

this.add = function(){// add a banner to the array
this.banners[this.banners.length] = [arguments[0], arguments[1]];
}

this.bind = function(){// bind to an element
if(typeof arguments[0] == 'string')
this.binding = document.getElementById(arguments[0]);
else
this.binding = arguments[0];
this.rotate();
}

this.rotate = function(){// the actual image rotator
if( ! this.empty())
return;
var showNum, tmpA = document.createElement('a'), tmpImg = document.createElement('img');

if(this.bannerNum < 0)// random
showNum = Math.floor(Math.random()*this.banners.length);
else// syncronous
showNum = this.bannerNum=(++this.bannerNum >= this.banners.length)?0:this.bannerNum;

tmpA.href = this.banners[showNum][0];
tmpImg.src = this.banners[showNum][1];
tmpA.appendChild(tmpImg);
this.binding.appendChild(tmpA);
}

this.empty = function(){// empty the element if possible
if(this.binding == null)
return false;
while(this.binding.hasChildNodes())
this.binding.removeChild(this.binding.firstChild);
return true;
}

this.startTimer = function(){// start the loop, normaly done during page load.
this.stopTimer();
this.timeout = window.setInterval(
(function(x){
return function(){
x.rotate();
}
})(this), this.timer*1000);
}

this.stopTimer = function(){// stop the loop, nice to make available via a button.
if(this.timeout != null)
window.clearInterval(this.timeout);
this.timeout = null;
}
}