// variables
var xOp7Up,xOp6Dn,xIE4Up,xIE4,xIE5,xNN4,xUA=navigator.userAgent.toLowerCase();
if(window.opera){
  var i=xUA.indexOf('opera');
  if(i!=-1){
    var v=parseInt(xUA.charAt(i+6));
    xOp7Up=v>=7;
    xOp6Dn=v<7;
  }
}
else if(navigator.vendor!='KDE' && document.all && xUA.indexOf('msie')!=-1){
  xIE4Up=parseFloat(navigator.appVersion)>=4;
  xIE4=xUA.indexOf('msie 4')!=-1;
  xIE5=xUA.indexOf('msie 5')!=-1;
}
else if(document.layers){xNN4=true;}
xMac=xUA.indexOf('mac')!=-1;


// functions

function xGetElementById(e)
{
  if(typeof(e)=='string') {
    if(document.getElementById) e=document.getElementById(e);
    else if(document.all) e=document.all[e];
    else e=null;
  }
  return e;
}

function xNum()
{
  for(var i=0; i<arguments.length; ++i){if(isNaN(arguments[i]) || typeof(arguments[i])!='number') return false;}
  return true;
}

function xDef()
{
  for(var i=0; i<arguments.length; ++i){if(typeof(arguments[i])=='undefined') return false;}
  return true;
}

function xStr(s)
{
  for(var i=0; i<arguments.length; ++i){if(typeof(arguments[i])!='string') return false;}
  return true;
}

function xClientHeight()
{
  var v=0,d=document,w=window;
  if((!d.compatMode || d.compatMode == 'CSS1Compat') && !w.opera && d.documentElement && d.documentElement.clientHeight)
    {v=d.documentElement.clientHeight;}
  else if(d.body && d.body.clientHeight)
    {v=d.body.clientHeight;}
  else if(xDef(w.innerWidth,w.innerHeight,d.width)) {
    v=w.innerHeight;
    if(d.width>w.innerWidth) v-=16;
  }
  return v;
}

function xAddEventListener(e,eT,eL,cap)
{
  if(!(e=xGetElementById(e)))return;
  eT=eT.toLowerCase();
  if(e.addEventListener)e.addEventListener(eT,eL,cap||false);
  else if(e.attachEvent)e.attachEvent('on'+eT,eL);
  else {
    var o=e['on'+eT];
    e['on'+eT]=typeof o=='function' ? function(v){o(v);eL(v);} : eL;
  }
}