// various functions related to viewable browser dimensions and scroll offset

putCenter: function(item) {
  item = $(item);
  var xy = item.getDimensions();
  var win = this.windowDimensions();
  var scrol = this.scrollOffset();
  item.style.left = (win[0] / 2) + scrol[0] - (xy.width / 2) + "px";
  item.style.top = (win[1] / 2) + scrol[1] - (xy.height / 2) + "px";
},
fullScreen: function(item) {
  item = $(item);
  var win = this.windowDimensions();
  var scrol = this.scrollOffset();
  item.style.height = scrol[1] + win[1] + "px";
},
windowDimensions: function() {
  var x, y;
  if (self.innerHeight) {
    // all except Explorer
    x = self.innerWidth;
    y = self.innerHeight;
  } else if (document.documentElement && document.documentElement.clientHeight) {
    // Explorer 6 Strict Mode
    x = document.documentElement.clientWidth;
    y = document.documentElement.clientHeight;
  } else if (document.body) {
    // other Explorers
    x = document.body.clientWidth;
    y = document.body.clientHeight;
  }
  if (!x) x = 0;
  if (!y) y = 0;
  arrayWindowSize = new Array(x,y);
  return arrayWindowSize;
},
scrollOffset: function() {
  var x, y;
  if (self.pageYOffset) {
    // all except Explorer
    x = self.pageXOffset;
    y = self.pageYOffset;
  } else if (document.documentElement && document.documentElement.scrollTop) {
    // Explorer 6 Strict
    x = document.documentElement.scrollLeft;
    y = document.documentElement.scrollTop;
  } else if (document.body) {
    // all other Explorers
    x = document.body.scrollLeft;
    y = document.body.scrollTop;
  }
  if (!x) x = 0;
  if (!y) y = 0;
  arrayScrollOffset = new Array(x,y);
  return arrayScrollOffset;
}