//Written by Manuel Villanueva
function bsa(form) {
var answer = Math.pow(form.kg.value,0.425) * Math.pow(form.cm.value,0.725) * 0.007184;
form.answer.value = Math.round(100*answer)/100;   

//if statements--
if(form.kg.value==""){
alert('Please enter kg');
form.kg.focus();
form.kg.select();
return false
}
if(form.cm.value==""){
alert('Please enter height');
form.cm.focus();
form.cm.select();
return false
}
}