hidden = false;

function hidecontent() {
	if(hidden == true) {
		document.getElementById("menu").style.visibility = 'visible';
		document.getElementById("sub_menu").style.visibility = 'visible';
		document.getElementById("subm").style.visibility = 'visible';
		document.getElementById("tcontent").style.visibility = 'visible';
		hidden = false;
		document.getElementById("ausblenden").innerHTML = "Inhalt ausblenden";
	} else {
		document.getElementById("menu").style.visibility = 'hidden';
		document.getElementById("sub_menu").style.visibility = 'hidden';
		document.getElementById("subm").style.visibility = 'hidden';
		document.getElementById("tcontent").style.visibility = 'hidden';
		hidden = true;
		document.getElementById("ausblenden").innerHTML = "Inhalt einblenden";
	}
}