function mod(div,base) {
	return Math.round(div - (Math.floor(div/base)*base));
}
function calcBmi() {
	var w = document.bmi.size1.value * 1;
	var h = document.bmi.size2.value * 1;
	displaysize = h;
	var rvalue = true;
	if ( (w < 68) || (w > 127)) {
	alert ("Fehler bei der Dateneingabe. Bitte wiederholen Sie die Eingabe!");
	document.forms[0].elements[0].select();
	document.forms[0].elements[0].focus();
	rvalue = false;
	}
	if ( ((h < 82) || (h > 155)) && (rvalue==true)) {
	alert ("Fehler bei der Dateneingabe. Bitte wiederholen Sie die Eingabe!");
	document.forms[0].elements[1].select();
	document.forms[0].elements[1].focus();
	rvalue = false;
	}
	if (((h-8) < w) && (rvalue==true)) {
	alert ("Fehler bei der Dateneingabe. Überbrustweite muss mindestens 8cm größer sein als Unterbrustweite. Bitte wiederholen Sie die Eingabe!");
	document.forms[0].elements[0].select();
	document.forms[0].elements[0].focus();
	rvalue = false;
	}
	if (((h-32) > w) && (rvalue==true)) {
	alert ("Fehler bei der Dateneingabe. Überbrustweite zu groß. Bitte wiederholen Sie die Eingabe!");
	document.forms[0].elements[0].select();
	document.forms[0].elements[0].focus();
	rvalue = false;
	}
	if (rvalue) {
	size_ger = (50+Math.round((w-50)/5)*5);
	size1 = Math.round(((h-8+1)-w)/2);
	document.bmi.size_ger.value = size_ger;
	if (size1==1)      size2_ger = "AAA" 
	else if (size1==2) size2_ger = "AA"
	else if (size1==3) size2_ger = "A";
	else if (size1==4) size2_ger = "B";
	else if (size1==5) size2_ger = "C";
	else if (size1==6) size2_ger = "D";
	else if (size1==7) size2_ger = "E";
	else if (size1==8) size2_ger = "F";
	else if (size1==9) size2_ger = "G";
	else if (size1==10) size2_ger = "H";
	else if (size1==11) size2_ger = "I";
	else if (size1==12) size2_ger = "J";
	else if (size1==13) size2_ger = "K";
	document.bmi.size2_ger.value = size2_ger;
	document.bmi.size_usa.value  = (24+Math.round((w-50)/5)*2);
	if (size1==1)      size2_usa = "AAA" 
	else if (size1==2) size2_usa = "AA"
	else if (size1==3) size2_usa = "A";
	else if (size1==4) size2_usa = "B";
	else if (size1==5) size2_usa = "C";
	else if (size1==6) size2_usa = "D";
	else if (size1==7) size2_usa = "E";
	else if (size1==8) size2_usa = "F";
	else if (size1==9) size2_usa = "G";
	else if (size1==10) size2_usa = "H";
	else if (size1==11) size2_usa = "I";
	else if (size1==12) size2_usa = "J";
	else if (size1==13) size2_usa = "K";
	document.bmi.size2_usa.value = size2_usa;
	
	document.bmi.size_uk.value   = (24+Math.round((w-50)/5)*2);
	if (size1==1)      size2_uk = "AAA" 
	else if (size1==2) size2_uk = "AA"
	else if (size1==3) size2_uk = "A";
	else if (size1==4) size2_uk = "B";
	else if (size1==5) size2_uk = "C";
	else if (size1==6) size2_uk = "D";
	else if (size1==7) size2_uk = "DD";
	else if (size1==8) size2_uk = "E";
	else if (size1==9) size2_uk = "F";
	else if (size1==10) size2_uk = "G";
	else if (size1==11) size2_uk = "H";
	else if (size1==12) size2_uk = "I";
	else if (size1==13) size2_uk = "J";
	document.bmi.size2_uk.value = size2_uk;
	document.bmi.size_fra.value  = (50+Math.round((w-50)/5)*5+15);
	if (size1==1)      size2_fra = "AAA" 
	else if (size1==2) size2_fra = "AA"
	else if (size1==3) size2_fra = "A";
	else if (size1==4) size2_fra = "B";
	else if (size1==5) size2_fra = "C";
	else if (size1==6) size2_fra = "D";
	else if (size1==7) size2_fra = "E";
	else if (size1==8) size2_fra = "F";
	else if (size1==9) size2_fra = "G";
	else if (size1==10) size2_fra = "H";
	else if (size1==11) size2_fra = "I";
	else if (size1==12) size2_fra = "J";
	else if (size1==13) size2_fra = "K";
	document.bmi.size2_fra.value = size2_fra;
	document.bmi.size_ita.value  = (Math.round((w-65)/5));
	if (size1==1)      size2_ita = "AAA" 
	else if (size1==2) size2_ita = "AA"
	else if (size1==3) size2_ita = "A";
	else if (size1==4) size2_ita = "B";
	else if (size1==5) size2_ita = "C";
	else if (size1==6) size2_ita = "D";
	else if (size1==7) size2_ita = "E";
	else if (size1==8) size2_ita = "F";
	else if (size1==9) size2_ita = "G";
	else if (size1==10) size2_ita = "H";
	else if (size1==11) size2_ita = "I";
	else if (size1==12) size2_ita = "J";
	else if (size1==13) size2_ita = "K";
	document.bmi.size2_ita.value = size2_ita;
	}
	return rvalue;
}
<!-- Copyright 2003, WEB-Design & Service, www.Buestenhalter.com //-->