var Position = {  // set to true if needed, warning: firefox performance problems  // NOT neeeded for page scrolling, only if draggable contained in  // scrollable elements  includeScrollOffsets: false,   // must be called before calling withinIncludingScrolloffset, every time the  // page is scrolled  prepare: function() {    this.deltaX =  window.pageXOffset                 || document.documentElement.scrollLeft                 || document.body.scrollLeft                 || 0;    this.deltaY =  window.pageYOffset                 || document.documentElement.scrollTop                 || document.body.scrollTop                 || 0;  },  realOffset: function(element) {    var valueT = 0, valueL = 0;    do {      valueT += element.scrollTop  || 0;      valueL += element.scrollLeft || 0;       element = element.parentNode;    } while (element);    return [valueL, valueT];  },  cumulativeOffset: function(element) {    var valueT = 0, valueL = 0;    do {      valueT += element.offsetTop  || 0;      valueL += element.offsetLeft || 0;      element = element.offsetParent;    } while (element);    return [valueL, valueT];  },  positionedOffset: function(element) {    var valueT = 0, valueL = 0;    do {      valueT += element.offsetTop  || 0;      valueL += element.offsetLeft || 0;      element = element.offsetParent;      if (element) {        p = Element.getStyle(element, 'position');        if (p == 'relative' || p == 'absolute') break;      }    } while (element);    return [valueL, valueT];  },    offsetParent: function(element) {    if (element.offsetParent) return element.offsetParent;    if (element == document.body) return element;    while ((element = element.parentNode) && element != document.body)      if (Element.getStyle(element, 'position') != 'static')        return element;    return document.body;  },    // caches x/y coordinate pair to use with overlap  within: function(element, x, y) {    if (this.includeScrollOffsets)      return this.withinIncludingScrolloffsets(element, x, y);    this.xcomp = x;    this.ycomp = y;    this.offset = this.cumulativeOffset(element);    return (y >= this.offset[1] &&            y <  this.offset[1] + element.offsetHeight &&            x >= this.offset[0] &&             x <  this.offset[0] + element.offsetWidth);  },  withinIncludingScrolloffsets: function(element, x, y) {    var offsetcache = this.realOffset(element);    this.xcomp = x + offsetcache[0] - this.deltaX;    this.ycomp = y + offsetcache[1] - this.deltaY;    this.offset = this.cumulativeOffset(element);    return (this.ycomp >= this.offset[1] &&            this.ycomp <  this.offset[1] + element.offsetHeight &&            this.xcomp >= this.offset[0] &&             this.xcomp <  this.offset[0] + element.offsetWidth);  },  // within must be called directly before  overlap: function(mode, element) {      if (!mode) return 0;      if (mode == 'vertical')       return ((this.offset[1] + element.offsetHeight) - this.ycomp) /         element.offsetHeight;    if (mode == 'horizontal')      return ((this.offset[0] + element.offsetWidth) - this.xcomp) /         element.offsetWidth;  },  clone: function(source, target) {    source = $(source);    target = $(target);    target.style.position = 'absolute';    var offsets = this.cumulativeOffset(source);    target.style.top    = offsets[1] + 'px';    target.style.left   = offsets[0] + 'px';    target.style.width  = source.offsetWidth + 'px';    target.style.height = source.offsetHeight + 'px';  },  page: function(forElement) {    var valueT = 0, valueL = 0;    var element = forElement;    do {      valueT += element.offsetTop  || 0;      valueL += element.offsetLeft || 0;      // Safari fix      if (element.offsetParent==document.body)        if (Element.getStyle(element,'position')=='absolute') break;    } while (element = element.offsetParent);    element = forElement;    do {      valueT -= element.scrollTop  || 0;      valueL -= element.scrollLeft || 0;        } while (element = element.parentNode);    return [valueL, valueT];  },  clone: function(source, target) {    var options = Object.extend({      setLeft:    true,      setTop:     true,      setWidth:   true,      setHeight:  true,      offsetTop:  0,      offsetLeft: 0    }, arguments[2] || {})    // find page position of source    source = $(source);    var p = Position.page(source);    // find coordinate system to use    target = $(target);    var delta = [0, 0];    var parent = null;    // delta [0,0] will do fine with position: fixed elements,     // position:absolute needs offsetParent deltas    if (Element.getStyle(target,'position') == 'absolute') {      parent = Position.offsetParent(target);      delta = Position.page(parent);    }    // correct by body offsets (fixes Safari)    if (parent == document.body) {      delta[0] -= document.body.offsetLeft;      delta[1] -= document.body.offsetTop;     }    // set position    if(options.setLeft)   target.style.left  = (p[0] - delta[0] + options.offsetLeft) + 'px';    if(options.setTop)    target.style.top   = (p[1] - delta[1] + options.offsetTop) + 'px';    if(options.setWidth)  target.style.width = source.offsetWidth + 'px';    if(options.setHeight) target.style.height = source.offsetHeight + 'px';  },  absolutize: function(element) {    element = $(element);    if (element.style.position == 'absolute') return;    Position.prepare();    var offsets = Position.positionedOffset(element);    var top     = offsets[1];    var left    = offsets[0];    var width   = element.clientWidth;    var height  = element.clientHeight;    element._originalLeft   = left - parseFloat(element.style.left  || 0);    element._originalTop    = top  - parseFloat(element.style.top || 0);    element._originalWidth  = element.style.width;    element._originalHeight = element.style.height;    element.style.position = 'absolute';    element.style.top    = top + 'px';;    element.style.left   = left + 'px';;    element.style.width  = width + 'px';;    element.style.height = height + 'px';;  },  relativize: function(element) {    element = $(element);    if (element.style.position == 'relative') return;    Position.prepare();    element.style.position = 'relative';    var top  = parseFloat(element.style.top  || 0) - (element._originalTop || 0);    var left = parseFloat(element.style.left || 0) - (element._originalLeft || 0);    element.style.top    = top + 'px';    element.style.left   = left + 'px';    element.style.height = element._originalHeight;    element.style.width  = element._originalWidth;  }}// Safari returns margins on body which is incorrect if the child is absolutely// positioned.  For performance reasons, redefine Position.cumulativeOffset for// KHTML/WebKit only.if (/Konqueror|Safari|KHTML/.test(navigator.userAgent)) {  Position.cumulativeOffset = function(element) {    var valueT = 0, valueL = 0;    do {      valueT += element.offsetTop  || 0;      valueL += element.offsetLeft || 0;      if (element.offsetParent == document.body)        if (Element.getStyle(element, 'position') == 'absolute') break;              element = element.offsetParent;    } while (element);        return [valueL, valueT];  }}