var currentMain = 1;

function showMain(id)

{

	document.getElementById('main_' + currentMain).style.display = 'none';

	document.getElementById('main_' + id).style.display = 'block';	

	currentMain = id;

	clearTimeout(timeout);

}



function showNextMain()

{

	document.getElementById('main_' + currentMain).style.display = 'none';

	if(currentMain == 4)

	{

		currentMain = 1;

	} else {

		currentMain++;

	}

	document.getElementById('main_' + currentMain).style.display = 'block';

}



var timeout = setInterval ( "showNextMain()", 9000 );