function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}

userAgent = window.navigator.userAgent;

browserVers = parseInt(userAgent.charAt(userAgent.indexOf("/")+1),10);

mustInitImg = true;

function initImgID() 
	{
		var di = document.images; 
		if (mustInitImg && di)
			{ 
				for (var i=0; i<di.length; i++) 
					{
						if (!di[i].id) di[i].id=di[i].name; 
					}
				mustInitImg = false;
			}
	}

function findElement(n,ly) 
	{
		var d = document;
		
		if (browserVers < 4) return d[n];
		
		if ((browserVers >= 6) && (d.getElementById)) 
			{
				initImgID;
				return(d.getElementById(n))
			} 
		
		var cd = ly ? ly.document : d;
		
		var elem = cd[n];
		
		if (!elem) 
			{
				for (var i=0;i<cd.layers.length;i++) 
					{
						elem = findElement(n,cd.layers[i]);
						if (elem) return elem;
					}
			}
		
		return elem;
	}

function changeImagesArray(array) 
{

	if (preloadFlag == true) 
		{
			var d = document; 
			var img;
			
			for (i=0;i<array.length;i+=2) 
				{
					img = null; var n = array[i];
					
					if (d.images) 
						{
							if (d.layers) 
								{
									img = findElement(n,0);
								}
							else 
								{
									img = d.images[n];
								}
						}
						
					if (!img && d.getElementById) 
						{
							img = d.getElementById(n);
						}
						
					if (!img && d.getElementsByName) 
						{
							var elms = d.getElementsByName(n);
							if (elms) 
								{
									for (j=0;j<elms.length;j++) 
										{
											if (elms[j].src) {img = elms[j]; break;}
										}
								}
						}
						
					if (img) 
						{
							img.src = array[i+1];
						}
				}
		}
}

function changeImages() 
	{
		changeImagesArray(changeImages.arguments);
	}


var preloadFlag = false;

function preloadImages() 
	{
		if (document.images) 
			{
				pre_tnav_coverage_over = newImage('media/tnav_coverage_over.jpg');
				pre_tnav_home_over = newImage('media/tnav_home_over.jpg');
				pre_tnav_aboutus_over = newImage('media/tnav_aboutus_over.jpg');
				pre_tnav_contactus_over = newImage('media/tnav_contactus_over.jpg');
				preloadFlag = true;
			}
	}