var prew_id = '';

function ShowElement(id){
		if(elem_1 = document.getElementById(id)){
//				elem_1.style.visibility = 'visible';
				elem_1.style.display = 'block';
				prew_id = id;
		}
}

function HideElement(id){
		if(elem_1 = document.getElementById(id)){
//				elem_1.style.visibility = 'hidden';
				elem_1.style.display = 'none';
				prew_id = '';
		}
}


function ChangeVisibility(id){
		elem_1 = document.getElementById(id);
		if(prew_id && prew_id != id){
				HideElement(prew_id);
		}
		
		if(elem_1.style.display == 'none'){
				ShowElement(id)
		}else{
				HideElement(id)
		}

}