function bascule(bloc)
{


 if(bloc=="section1") {
	 document.getElementById('section1').style.display="block"; 
	 document.getElementById('section2').style.display="none"; 
	 document.getElementById('section3').style.display="none"; 
	 }
  if(bloc=="section2") {
	 document.getElementById('section1').style.display="none"; 
	 document.getElementById('section2').style.display="block"; 
	 document.getElementById('section3').style.display="none"; 
	 }
	
  if(bloc=="section3") {
	 document.getElementById('section1').style.display="none"; 
	 document.getElementById('section2').style.display="none"; 
	 document.getElementById('section3').style.display="block"; 
	 }


}