function trocaImagem(imgObj)
{
	src = imgObj.src; 
	if(src.indexOf("__on")!=-1)
	{
		srcNew = src.replace("__on","__off"); 
	}
	else
	{
		srcNew = src.replace("__off","__on"); 
	}
	
	imgObj.src = srcNew; 
}


function loadImgOver()
{
	overImagesArray = document.getElementsByTagName("img"); 
	
	for(i=0;i<overImagesArray.length;i++)
	{
		isOver = overImagesArray[i].getAttribute("over")=="true";

		if(isOver) 
		{
			overImagesArray[i].onmouseover = function()
			{
				trocaImagem(this);
			}
			
			overImagesArray[i].onmouseout = function()
			{
				trocaImagem(this);
			}
		}
	}
}