<!-- Concrete Materials Calculators

function calcConc(form) {
    var concAmt = 0;
    for (var i = 1; i <= 3; i++) {
       var parsecheck = "" + parseFloat(form.elements[i].value);
       if (parseFloat(form.elements[i].value) < 0 ||
           parseFloat(form.elements[i].value) == 0 ||
           parsecheck == "NaN") {
          window.alert("Please enter a positive number in each of the " +
                       "three input fields.");
          return false;
       }
    }
    if (form.elements[5].checked == true) 
       concAmt = form.elements[1].value * form.elements[2].value *
                 (form.elements[3].value / 12.0) / 27;
    else 
       concAmt = form.elements[1].value * form.elements[2].value *
                 form.elements[3].value / 27;
    form.elements[7].value = formatvalue(concAmt,7);
    return true;
}
function calcCol(form) {
    var concAmt = 0;
    for (var i = 1; i <= 2; i++) {
       var parsecheck = "" + parseFloat(form.elements[i].value);
       if (parseFloat(form.elements[i].value) < 0 ||
           parseFloat(form.elements[i].value) == 0 ||
           parsecheck == "NaN") {
          window.alert("Please enter a positive number in both of the " +
                       "two input fields.");
          return false;
       }
    }
    var radius = form.elements[2].value / 24.0;
    concAmt = form.elements[1].value * radius * radius * Math.PI / 27;
    form.elements[4].value = formatvalue(concAmt,7);
    return true;
}
function calcWall(form)  {
    var concAmt = 0;
    for (var i = 1; i <= 2; i++) {
       var parsecheck = "" + parseFloat(form.elements[i].value);
       if (parseFloat(form.elements[i].value) < 0 ||
           parseFloat(form.elements[i].value) == 0 ||
           parsecheck == "NaN") {
          window.alert("Please enter a positive number in both of the " +
                       "two input fields.");
          return false;
       }
    }
    if (form.elements[3].checked == true)
       concAmt = form.elements[1].value * form.elements[2].value * 0.32 / 27.0;
    else
       concAmt = form.elements[1].value * form.elements[2].value * 0.51 / 27.0;
    form.elements[6].value = formatvalue(concAmt,7);
    return true;
}
function formatvalue(input, rsize) {
   var invalid = "**************************";
   var nines = "999999999999999999999999";
   var strin = "" + input;
   var fltin = parseFloat(strin);
   if (strin.indexOf("e") != -1 ||
       fltin > parseFloat(nines.substring(0,rsize)+".4"))
      return invalid.substring(0, rsize);
   if (strin.length <= rsize) return strin;
   var rounded = "" + (fltin + 
      (fltin - parseFloat(strin.substring(0, rsize))));
   return rounded.substring(0, rsize);
}
function clearform(form,count,lastElement) {
    for (var i = 1; i <= count; i++) form.elements[i].value = "";
    form.elements[lastElement].value = "";
}