function change_bg(q,id)
{ 
document[id].src=q;
}
function show(id){
	document.getElementById(id).style.visibility = 'visible';
	document.getElementById(id).style.position ='static';
}
function hide(id){	
	document.getElementById(id).style.visibility = 'hidden';
	document.getElementById(id).style.position ='absolute';	
	document.getElementById(id).style.left = "-1000px";
	document.getElementById(id).style.top = "-1000px";
}
function isHidden(id){
	if (document.getElementById(id).style.visibility == 'hidden') return true;
	else return false;
}