function changetxt(txt) {
	document.getElementById("txt1").style.display="none";
	document.getElementById("txt2").style.display="none";
	document.getElementById("txt3").style.display="none";
	document.getElementById("txt4").style.display="none";
	document.getElementById("txt5").style.display="none";
	document.getElementById(txt).style.display="block";
}