function changeLevel(crl) {
	if (crl == "level1") {
	document.getElementById("default-text").style.display="none";
    document.getElementById("level1").style.display="block";
	document.getElementById("level2").style.display="none";
	document.getElementById("level3").style.display="none";
	} else if (crl == "level2") {
	document.getElementById("default-text").style.display="none";
    document.getElementById("level1").style.display="none";
	document.getElementById("level2").style.display="block";
	document.getElementById("level3").style.display="none";
	} else if (crl == "level3") {
	document.getElementById("default-text").style.display="none";
    document.getElementById("level1").style.display="none";
	document.getElementById("level2").style.display="none";
	document.getElementById("level3").style.display="block";
	}else {
	document.getElementById("default-text").style.display="block";
    document.getElementById("level1").style.display="none";
	document.getElementById("level2").style.display="none";
	document.getElementById("level3").style.display="none";
	}
    }