function txt_roll(str) {
	var anim = new YAHOO.util.Anim( str );
	anim.duration = 0.5;
	//if ( document.getElementById( str ).style.display == "none" ) document.getElementById( str ).style.display = "";
	if ( !anim.isAnimated() )
	{
		if ( document.getElementById( str ).style.display == "none" ) 
		{
			document.getElementById( str ).style.display = "block";
		    var attributes = {
	            height: { to: anim.getAttribute( 'height' ), from: 0, unit:'px' }
	        };
		    anim.attributes = attributes;
	        anim.onComplete.subscribe( function(){
	        	document.getElementById( str ).style.display = "";
	        }) ;
	        anim.animate()
		}
		else if ( document.getElementById( str ).style.display == "" )
		{
			document.getElementById( str ).style.display = "block";
		    var attributes = {
		    		height: { to: '0' }
		        };
		    anim.attributes = attributes;
	        anim.onComplete.subscribe( function(){
	        	document.getElementById( str ).style.display = "none";
	        	document.getElementById( str ).style.height = "auto";
	        }) ;
		    anim.animate();
		}
	}
}

/*
function txt_roll(str) {
	if ( document.getElementById( str ).style.display == "none" ) document.getElementById( str ).style.display = "";
	else if ( document.getElementById( str ).style.display == "" ) document.getElementById( str ).style.display = "none";
	else return false;
}

*/