var assistance = 0;
	function activer_devis(){		
		document.getElementById('prix_voyage').onkeyup = function(){
			if(isNaN(this.value)){
				document.getElementById('prix_assurance').value ='';
				document.getElementById('prix_annulation').value ='';			
			} else {
				document.getElementById('prix_assurance').value = (parseFloat(this.value)*0.0017+5.3).toFixed(2);
				document.getElementById('prix_annulation').value = (parseFloat(this.value)*0.0196).toFixed(2);
			}
			calculer();
			
		}
			for(var i=1;i<24;i++){
				document.getElementById('prix_assistance'+i).onclick = function(){
					assistance=parseFloat(this.value);
					calculer();
				} ;
			}
		function calculer(){
			var total = (assistance + parseFloat(document.getElementById('prix_assurance').value)+parseFloat(document.getElementById('prix_annulation').value)).toFixed(2);
			if(isNaN(total))document.getElementById('prix_total').value ='';
			 else document.getElementById('prix_total').value = total;
		}
	}
	addLoadEvent(activer_devis);