if (document.getElementById) { window.onload = swap };
function swap() {
var numimages=7;
rndimg = new Array("backgrounds/background_01.jpg", "backgrounds/background_02.jpg", "backgrounds/background_03.jpg", "backgrounds/background_04.jpg", "backgrounds/background_05.jpg", "backgrounds/background_06.jpg", "backgrounds/background_07.jpg"); 
x=(Math.floor(Math.random()*numimages));
randomimage=(rndimg[x]);
document.getElementById("background").style.backgroundImage = "url("+ randomimage +")"; 
}

<!--
function MM_preloadImages() { //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=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_swapImgRestore() { //v3.0
  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_findObj(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=MM_findObj(n,d.layers[i].document);
  if(!x && d.getElementById) x=d.getElementById(n); return x;
}

function MM_swapImage() { //v3.0
  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];}
}
//-->

var scroller_timer;

function DoScrollerNav (div_name,min_height)
{
	if (document.getElementById(div_name).scrollHeight > min_height)
		ShowDiv ('scroller_nav')
	else
		HideDiv ('scroller_nav')	
}

function move_up(div_name) 
{
   document.getElementById(div_name).scrollTop -= 10;
   scroller_timer = setTimeout('move_up(\''+div_name+'\')',100);

}

function move_down(div_name) 
{
   document.getElementById(div_name).scrollTop += 10;
   scroller_timer = setTimeout('move_down(\''+div_name+'\')', 100);   
}

if (document.images) {

    aboutusup       = new Image();
    aboutusup.src   = "images/aboutpre.gif" ;
    aboutusdown     = new Image() ;
    aboutusdown.src = "images/aboutpost.gif" ;
    
    installup       = new Image();
    installup.src   = "images/installpre.gif" ;
    installdown     = new Image() ;
    installdown.src = "images/installpost.gif" ;
    
    monitorup       = new Image();
    monitorup.src   = "images/monitorpre.gif" ;
    monitordown     = new Image() ;
    monitordown.src = "images/monitorpost.gif" ;
    
    serviceup       = new Image();
    serviceup.src   = "images/servicepre.gif" ;
    servicedown     = new Image() ;
    servicedown.src = "images/servicepost.gif" ;
    
    cctvup       = new Image();
    cctvup.src   = "images/cctvpre.gif" ;
    cctvdown     = new Image() ;
    cctvdown.src = "images/cctvpost.gif" ;
    
	digitalup       = new Image();
    digitalup.src   = "images/digpre.gif" ;
    digitaldown     = new Image() ;
    digitaldown.src = "images/digpost.gif" ;
	
    frequentlyup       = new Image();
    frequentlyup.src   = "images/faqpre.gif" ;
    frequentlydown     = new Image() ;
    frequentlydown.src = "images/faqpost.gif" ;
    
    contactusup       = new Image();
    contactusup.src   = "images/contactpre.gif" ;
    contactusdown     = new Image() ;
    contactusdown.src = "images/contactpost.gif" ;

}

function buttondown( buttonname )
{
    if (document.images) {
      document[ buttonname ].src = eval( buttonname + "down.src" );
    }
}

function buttonup ( buttonname )
{
    if (document.images) {
      document[ buttonname ].src = eval( buttonname + "up.src" );
    }
}



function ShowDiv (div_name)
{
	document.getElementById(div_name).className 				= "visible";	

}

function HideDiv (div_name)
{
	document.getElementById(div_name).className 				= "invisible";
}

function MM_openBrWindow(theURL,winName,features) { //v2.0
  window.open(theURL,winName,features);
}