function opac()
{
	var obj_img = document.getElementById('footer_1').getElementsByTagName('img');
	if (obj_img.length>0)
	{
		for (a=0;a<obj_img.lenght ;a++)
		{
			obj_img[a].onMouseOver = function()
			{
				this.className = "over";
			}
			obj_img[a].onMouseOut = function()
			{
				this.className = "";
			}
		}
	}
}