function change ( title ) 
{
	if ( !document.getElementById ) 
		return true;
	for (var i = 0; i < mainmenus.length; i ++) 
		{
		if ( mainmenus.join(',').indexOf(title) > -1 ) 
			{
			if (mainmenus[i] != title) 
				{
				document.getElementById ( mainmenus[i] ).style.display = 'none';
				}
			}
		}
	title = document.getElementById( title );
	title.style.display = ( title.style.display == 'block' ) ? 'none' : 'block';
	return false;
}