// JavaScript Document
/* This script and many more are available free online at
The JavaScript Source!! http://javascript.internet.com
Created by: Jay Rumsey | http://www.nova.edu/~rumsey/ */

function UpdateCost() {
  var sum = 0;
  var gn, elem;
  for (i=0; i<5; i++) {
    gn = 'item'+i;
    elem = document.getElementById(gn);
	gn1 = 'pre'+i;
    elem1 = document.getElementById(gn1);
    if (elem.checked == true) { sum += Number(elem1.value); }
  }
  document.getElementById('totalcost').value = sum;
}