function calcs() 
{
var con_of_box1 =(document.form1.box1.value);
var con_of_box2 =(document.form1.box2.value);
var con_of_box3 =(document.form1.box3.value);

var subtotal = con_of_box1 / con_of_box2 / con_of_box3;

document.form1.subtotal.value =subtotal;

}