var theImages = new Array(); 

theImages[0] = 'images/header1.jpg';
theImages[1] = 'images/header2.jpg';
theImages[2] = 'images/header3.jpg';
theImages[3] = 'images/header4.jpg';
theImages[4] = 'images/header5.jpg';
theImages[5] = 'images/header6.jpg';
theImages[6] = 'images/header7.jpg';
theImages[7] = 'images/header8.jpg';
theImages[8] = 'images/header9.jpg';
theImages[9] = 'images/header10.jpg';
theImages[10] = 'images/header11.jpg';
theImages[11] = 'images/header12.jpg';
theImages[12] = 'images/header13.jpg';
theImages[13] = 'images/header14.jpg';
theImages[14] = 'images/header15.jpg';
theImages[15] = 'images/header16.jpg';
theImages[16] = 'images/header17.jpg';
theImages[17] = 'images/header18.jpg';
theImages[18] = 'images/header19.jpg';
theImages[19] = 'images/header20.jpg';
theImages[20] = 'images/header21.jpg';

var j = 0;
var p = theImages.length;

var preBuffer = new Array();
for (i = 0; i < p; i++){
   preBuffer[i] = new Image();
   preBuffer[i].src = theImages[i]
}

var whichImage = Math.round(Math.random()*(p-1));

var theSloganImages = new Array();
theSloganImages[0] = 'images/slogan_excel.gif';
theSloganImages[1] = 'images/slogan_achievement.gif';
theSloganImages[2] = 'images/slogan_future.gif';
theSloganImages[3] = 'images/slogan_education.gif';

var sloganlen = theSloganImages.length;
var sloganPreBuffer = new Array();
for (var i = 0; i < sloganlen; i++)
{
	sloganPreBuffer[i] = new Image();
	sloganPreBuffer[i].src = theSloganImages[i];
}
var whichSloganImage = Math.round(Math.random()*(sloganlen-1));

function showImage()
{	
	banner.style.background='url(' + theImages[whichImage]+ ')';
	slogan.style.background='url(' + theSloganImages[whichSloganImage] + ')';
}