function test_champ(champ) {
	champ.value = champ.value.replace(/,/, ".") ;
	if (!isFinite(champ.value)) {
		alert ("Veuillez entrer un nombre.") ;
		champ.value = "" ;
		exit();		
	}
	if (parseInt(champ.value) < 0) {
		alert ("Veuillez entrer une valeur positive.") ;
		champ.value = "" ;
		exit();		
	}
	switch (champ.name) {
		case "degrePotentiel" :
			if (champ.value < 5 || champ.value > 20) {
				alert ("Veuillez entrer un degré compris entre 5 et 20.") ;
				champ.value = "" ;				
			}
			break;
		case "degreFinal" :
			if (champ.value < 5 || champ.value > 20) {
				alert ("Veuillez entrer un degré compris entre 5 et 20.") ;
				champ.value = "" ;				
			}
			break;		
	}
   calcul_form() ;
}


function valide_champ (champ) {
	return (isFinite(champ.value) && champ.value != 0 && champ.value != "");
}

function calcul_form() {
	
	var saccharose1, saccharose2, saccharose3, mout1, mout2, mout3;
	
	if (document.forms.form1.degrePotentiel.value!="" && document.forms.form1.degreFinal.value!="" && document.forms.form1.mout.value!="" ){
		
	
		saccharose1 = (((document.forms.form1.degreFinal.value*16.83) - (document.forms.form1.degrePotentiel.value*16.83))/(1586-(document.forms.form1.degreFinal.value*16.83)))*document.forms.form1.mout.value*158.6*342/360;
	
		mout1 = 100*document.forms.form1.mout.value*16.83*(document.forms.form1.degrePotentiel.value-document.forms.form1.degreFinal.value)/((document.forms.form1.degreFinal.value*16.5)-document.forms.form1.concentrationSucre.value);
	
		saccharose2 = (((document.forms.form1.degreFinal.value*16.5)-(document.forms.form1.degrePotentiel.value*16.83))/(1586-(document.forms.form1.degreFinal.value*16.5)))*document.forms.form1.mout.value*158.6*342/360;
	
		mout2 = 100*document.forms.form1.mout.value*((16.83*document.forms.form1.degrePotentiel.value)-(16.5*document.forms.form1.degreFinal.value))/((document.forms.form1.degreFinal.value*16.5)-document.forms.form1.concentrationSucre.value);
	
		saccharose3 = (((document.forms.form1.degreFinal.value*17)-(document.forms.form1.degrePotentiel.value*16.83))/(1586-(document.forms.form1.degreFinal.value*17)))*document.forms.form1.mout.value*158.6*342/360;		
	
		mout3 = 100*document.forms.form1.mout.value*((16.83*document.forms.form1.degrePotentiel.value)-(17*document.forms.form1.degreFinal.value))/((document.forms.form1.degreFinal.value*17)-document.forms.form1.concentrationSucre.value);
		
		if (isFinite(saccharose1) && saccharose1 != 0) {
				document.forms.form1.saccharose1.value = saccharose1.toFixed(3) ;
		}
		if (isFinite(mout1) && mout1 != 0) {
				document.forms.form1.mout1.value = mout1.toFixed(3) ;
		}
		if (isFinite(saccharose2) && saccharose2 != 0) {
				document.forms.form1.saccharose2.value = saccharose2.toFixed(3) ;
		}
		if (isFinite(mout2) && mout2 != 0) {
				document.forms.form1.mout2.value = mout2.toFixed(3) ;
		}
		if (isFinite(saccharose3) && saccharose3 != 0) {
				document.forms.form1.saccharose3.value = saccharose3.toFixed(3) ;
		}
		if (isFinite(mout3) && mout3 != 0) {
				document.forms.form1.mout3.value = mout3.toFixed(3) ;
		}
	
	}
	
/*	
	if (document.forms.form1.SecvPr) {
		var secv, pr, he ;
		secv = (((2 * document.forms.form1.H.value) *1 + document.forms.form1.L.value *1) * (1 - document.forms.form1.T.value / 100)) / document.forms.form1.E.value ;
		pr = document.forms.form1.Tha.value / 10 ;
		he = document.forms.form1.H.value / document.forms.form1.E.value
		secvpr = secv / pr ;
		if (isFinite(secv) && secv != 0) {
			document.forms.form1.Secv.value = secv.toFixed(2) ;
		}
		if (isFinite(pr) && pr != 0) {
			document.forms.form1.Pr.value = pr.toFixed(2) ;
		}
		if (isFinite(he) && he != 0) {
			document.forms.form1.HE.value = he.toFixed(1) ;
		}
		if (isFinite(secvpr) && secvpr != 0) {
			document.forms.form1.SecvPr.value = secvpr.toFixed(1) ;
		}
	}
	else if (document.forms.form1.so2Actif
					 && valide_champ(document.forms.form1.so2Libre)
					 && valide_champ(document.forms.form1.ph)
					 && valide_champ(document.forms.form1.tav)
					 && valide_champ(document.forms.form1.temp)) {
		var myVar, so2, rec1, rec2;
		myVar = Math.pow(10, ((0.02 * document.forms.form1.tav.value) + (0.031 * document.forms.form1.temp.value) + 1.10 - document.forms.form1.ph.value));
		so2 = document.forms.form1.so2Libre.value * myVar;
		rec1 = .35 / myVar;
		rec2 = .6 / myVar;
		if (isFinite(so2) && so2 != 0) {
			document.forms.form1.so2Actif.value = so2.toFixed(2) ;
		}
		if (isFinite(rec1) && rec1 != 0) {
			document.forms.form1.so2Min.value = Math.round(rec1) ;
		}
		if (isFinite(rec2) && rec2 != 0) {
			document.forms.form1.so2Max.value = Math.round(rec2) ;
		}
	}
*/	

}