var hoehe=screen.availHeight

var big=(hoehe>600);
function checkScreen() 
{
	if(document.layers)
		{
		document.layers["navojs"].visibility="hidden";
		}
	if(document.all)
		{
		document.all["navojs"].style.visibility="hidden";
		}
	if(document.getElementById)
		{
		document.getElementById("navojs").style.visibility="hidden";
		}
	if (big==1) 
	{
	if(document.all)
		{
		document.all["maindoc"].className="zentrierenbig";
		}
	if(document.getElementById)
		{
		document.getElementById("maindoc").className="zentrierenbig";

		}
	}

	if (big==0) 
	{
	if(document.all)
		{
		document.all["maindoc"].className="zentrierensmall";
		}
	if(document.getElementById)
		{
		document.getElementById("maindoc").className="zentrierensmall";
		}
	}

}