// JavaScript Document
function cal_csi(cigs, price, time) {
   csi = (cigs * (price / 20) * time);
   //window.alert(csi + "; " + cigs + "; " + time);
   f_csi = Math.floor(csi);
   diff  = csi - f_csi;
   diff = diff * 100;
   //window.alert(diff);
   diff = Math.round(diff);
   //window.alert(diff);

   if (diff == 10) {
      // Need to bump up the whole thing instead
      f_csi += 1;
      diff = 0;
   }

   if (diff == 0) {
	diff = "00";
   }

   csi = "$" + f_csi + "." + diff;
   return csi;
}

function compute() {
   var f = document.csi_input;
   var cigs = parseInt(f.cigs.value);
   var price = f.price.value;
   var time = parseInt(f.time.options[f.time.selectedIndex].value);
   //window.alert(cigs + "; " + price + "; " + time);

   if (chkw(cigs)){
		if (chkw(price)){
			f.csi.value = cal_csi(cigs, price, time);
		} else {
			f.price.focus();
			alert("Please enter a number for your price."); 
		}
   } else { 
			f.cigs.focus();
      alert("Please enter a number for the number of cigarettes per day."); 
   }
   // Set cookies for future views of this page
   // Expires when user closes browser
   document.cookie = "csi=" + f.csi.value;
   document.cookie = "cigs=" + f.cigs.value;
   document.cookie = "price=" + f.price.value;
   document.cookie = "time=" + f.time.selectedIndex;
}

function chkw(w) {
   if (isNaN(parseInt(w))) {
      return false;
   } else if (w < 0) {
      return false;
   }
   else {
      return true;
   }
}

function load_cookies() {
	var f = document.csi_input;
	f.cigs.value = loadcookie("cigs");
	f.price.value = loadcookie("price");
	f.csi.value = loadcookie("csi");
	f.time.selectedIndex = loadcookie("time");
}

function loadcookie(name) {
    var allcookies = document.cookie;
	var value;
	var pos = allcookies.indexOf(name + "=");
	//alert("Name: " + name + " All: " + allcookies);
	var len = name.length + 1;  // length of name + 1
	if (pos != -1) {
		var start = pos + len;  //Start of cookie value
		var end = allcookies.indexOf(";", start);  //End of cookie value
		if (end == -1) end = allcookies.length;
		value = allcookies.substring(start,end); //Extract the value
		//alert("Name: " + name + " Value: " + value);
		value = unescape(value);  // Decode it, if encoded.
    	return value;
	}

    return 0;
}