MM_preloadImages('images/nav_home2.gif','images/nav_commercial2.gif','images/nav_industrial2.gif','images/nav_residential2.gif','images/nav_boilers2.gif','images/nav_about2.gif','images/nav_careers2.gif','images/nav_search2.gif')

function MM_swapImgRestore(){
var i,x,a=document.MM_sr;
for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;
}

function MM_preloadImages(){
var d=document;

if(d.images){
  if(!d.MM_p) d.MM_p=new Array();
  var i,j=d.MM_p.length,a=MM_preloadImages.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];
  }
 }
}

function MM_findObj(n, d)
{
 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=MM_findObj(n,d.layers[i].document);
if(!x && document.getElementById) x=document.getElementById(n);
return x;
}

function MM_swapImage()
{
var i,j=0,x,a=MM_swapImage.arguments;
document.MM_sr=new Array; 
for(i=0;i<(a.length-2);i+=3)
if ((x=MM_findObj(a[i]))!=null)
{
document.MM_sr[j++]=x;
if(!x.oSrc) x.oSrc=x.src;

x.src=a[i+2];
}
}