var isVisible=0;

function flip_visible()
{
	var alltags=document.getElementsByTagName("div")
	isVisible ^=1;
	for (i=0; i<alltags.length; i++)
	{
		switch (alltags[i].className)
		{
			case "dop4":
				alltags[i].style.visibility=isVisible ? "visible" : "hidden";
				break;

			case "dop3":
			{
				alltags[i].style.width = isVisible?365:660;
				alltags[i].style.left = isVisible?300:0;
			}
		}

	}
	if (window.event) event.returnValue=false;
}