/*
* Copyright 2006 Ronny Engelmann
* This code is free; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation
* Contact Ronny Engelmann at ronny.engelmann [at] knoxmic [dot] net
*
* Description: scrolling content with javascript
*/

function scroll(objElement, intHeight) {
  var self = this;
  this._y = 0;
  objElement.style.top  = "0px";

  this.setPosition = function(intPos, y) {
    if (intPos > 0) intPos = 0;
    if (intPos < intHeight - objElement.offsetHeight)
      intPos = intHeight - objElement.offsetHeight;
    this._y = intPos;
    objElement.style.top  = this._y +"px";
  };

  this.scrollY = function(y) { this.setPosition(this._y + y, y); };

  this.start = function(y) {
    this.scrollTimer = window.setInterval(
      function() { self.scrollY(y); }, 25 );
  };
  this.stop = function() {
    if (this.scrollTimer) window.clearInterval(this.scrollTimer); };
};