function calcCurrencyCount(form){
	var i1 = form.currency1.value;
	var i2 = form.currency2.value;
	var a = (i1 != 0) ? currencies[i1] : 1
	var b = (i2 != 0) ? currencies[i2] : 1
	form.value2.value = form.value1.value * (a / b);
}