// Intercambio de imagenes
<!--
function buscarObj(n, d) { //v4.01
  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=buscarObj(n,d.layers[i].document);
  if(!x && d.getElementById) x=d.getElementById(n); return x;
}
function cambiar() { //v3.0
  var i,j=0,x,a=cambiar.arguments; document.imagen=new Array; for(i=0;i<(a.length-2);i+=3)
   if ((x=buscarObj(a[i]))!=null){document.imagen[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}
}
function restaurar() { //v3.0
  var i,x,a=document.imagen; for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;
}

function precarga() { //v3.0
  var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
    var i,j=d.MM_p.length,a=precarga.arguments; for(i=0; i<a.length; i++)
    if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}

//-->
/***********************************************
* Drop Down/ Overlapping Content- © Dynamic Drive
(www.dynamicdrive.com)
* This notice must stay intact for legal use.
* Visit http://www.dynamicdrive.com/ for full source code
***********************************************/
function getposOffset(overlay, offsettype){
var totaloffset=(offsettype=="right")? overlay.offsetLeft :
overlay.offsetTop;
var parentEl=overlay.offsetParent;
while (parentEl!=null){
totaloffset=(offsettype=="left")? totaloffset+parentEl.offsetLeft :
totaloffset+parentEl.offsetTop;
parentEl=parentEl.offsetParent;
}
return totaloffset;
}
function overlay(curobj, subobjstr, opt_position){
if (document.getElementById){
var subobj=document.getElementById(subobjstr)
subobj.style.display=(subobj.style.display!="block")? "block" : "none"
var xpos=getposOffset(curobj, "left")+((typeof
opt_position!="undefined" &&
opt_position.indexOf("left")!=-1)?
-(subobj.offsetWidth-curobj.offsetWidth) : 90) 
var ypos=getposOffset(curobj, "bottom")+((typeof opt_position!="undefined"
&& opt_position.indexOf("top")!=-1)? curobj.offsetHeight : -55)
subobj.style.left=xpos+"px"
subobj.style.top=ypos+"px"
return false
}
else
return true
}
function overlayclose(subobj){
document.getElementById(subobj).style.display="none"
}