var Images = new Array();
var PImages = new Array();

var SelNavBtnName = "";
var SelNavBtn = null;


function PreloadImages()
{
    PImages = new Array(Images.length * 2);

    imgcnt = 0;

    for (i = 0; i < Images.length; i++)
	{
        PImages[imgcnt] = new Image();
        PImages[imgcnt].src = Images[i].regImgUrl;
        imgcnt++;
        PImages[imgcnt] = new Image();
        PImages[imgcnt].src = Images[i].hoverImgUrl;
        imgcnt++;
    }

    SelNavBtn = document.getElementById(SelNavBtnName);
    if (SelNavBtn == null) return;

    for (i = 0; i < Images.length; i++)
    {
        if (Images[i].imageName == SelNavBtnName)
        {
            SelNavBtn.src = Images[i].hoverImgUrl;
            break;
        }
    }
}

function NavButtonMouseOver(btnID)
{
    btn = document.getElementById(btnID);
    if (btnID == SelNavBtnName) return;
    if (PImages == null || PImages.length == 0) return;

    for (i = 0; i < Images.length; i++)
    {
        if (Images[i].imageName == btnID)
		{
			btn.src = Images[i].hoverImgUrl;
			break;
		}
    }
}

function NavButtonMouseOut(btnID)
{
    btn = document.getElementById(btnID);
    if (btnID == SelNavBtnName) return;
    if (PImages == null || PImages.length == 0) return;
	
	for (i = 0; i < Images.length; i++)
	{
	    if (Images[i].imageName == btnID)
		{
			btn.src = Images[i].regImgUrl;
			break;
		}
	}
}

function SetSelectedNavButton(btnID) 
{
    for (i = 0; i < Images.length; i++)
    {
        id = Images[i];
        document.getElementById(id.imageName).src = id.regImgUrl;
    }
    
    SelNavBtnName = btnID;
}

function ImageDefinition(imgName, rImgUrl, hImgUrl)
{
	this.imageName = imgName;
	this.regImgUrl = rImgUrl;
	this.hoverImgUrl = hImgUrl;
}