function showhistory (dat)
{
	if (document.getElementById('mu_history_text_'+dat).style.visibility !== 'visible')
	{
		document.getElementById('mu_history_text_'+dat).style.visibility='visible';
		//document.getElementById('mu_history_text_'+dat).style.position='relative';
	}
	else 
	{
		document.getElementById('mu_history_text_'+dat).style.visibility='hidden';
		//document.getElementById('mu_history_text_'+dat).style.position='absolute';
	}
}