Golf Handicap Index Calculator

This is a fairly simple script that will calculate your golf handicap index according to the USGA's formula.

Each round of golf is first calculated with the USGA's formula of (Score - Course Rating) * 113 /Slope Rating. Depending on the number of rounds entered, a certian number of lowest rounds are then dropped. An average of the remaining differentials is calculated. The average is then multiplied by .96 to get the final handicap index.

Here is how the code works.

When the form is submitted there will be a comma delimited list for each of the form fields and an array will be created for each of the neccesary values for the formula.

Each matching set of values will be calculated and the results will be stored into an array.

To accomodate the number of values that are dropped, the array will then be sorted according to value and ran through a loop stopping at the appropriate number of values. During that loop, the values will be added together.

The sum of the values will be then averages (divided by the number of values) and then multiplied by .96 to get the resulting golf handicap index value.

Normally a minimum of five rounds of 18 holes of golf is required to get an accurate handicap index, but for the sake of demonstration and to give you a general idea of your handicap index, only one is required.

Here is the ASP code and the JavaScript code for this process:

<%

  If Request("DoStuff") = "Calculate Handicap" Then

     Sub SortArray(TheArr,AscDesc)
      TempVal = ""
      For x = 0 to UBound(TheArr)

         For y = x+1 to UBound(TheArr)
            If AscDesc = "Desc" Then
              If Cdbl(TheArr(x)) < CDbl(TheArr(y)) then
                 TempVal = TheArr(y)
                 TheArr(y) = TheArr(x)
                 TheArr(x) = TempVal
              End If
            Else
              If Cdbl(TheArr(x)) > Cdbl(TheArr(y)) then
                 TempVal = TheArr(x)
                 TheArr(x) = TheArr(y)
                 TheArr(y) = TempVal
              End If
            End If
         Next

      Next

     End Sub

     dim DiffArr()
     RoundNumArr = Split(Request("RoundNum"),",")
     ScoreArr = Split(Request("Score"),",")
     RatingArr = Split(Request("Rating"),",")
     SlopeArr = Split(Request("Slope"),",")
     NumRounds = UBound(RoundNumArr)

     For x = 0 To UBound(RoundNumArr)-1
       ReDim Preserve DiffArr(x)
       DiffArr(x) = CDbl((ScoreArr(x)-RatingArr(x))*113/SlopeArr(x)) & ","
     Next

     Call SortArray(DiffArr,"Desc")

     If NumRounds < 5 Then
     ElseIf NumRounds <= 6 Then
        NumRounds = NumRounds - 1
     ElseIf NumRounds <= 8 Then
         NumRounds = NumRounds - 2
     ElseIf NumRounds <= 10 Then
         NumRounds = NumRounds - 3
     ElseIf NumRounds <= 12 Then
         NumRounds = NumRounds - 4
     ElseIf NumRounds <= 14 Then
         NumRounds = NumRounds - 5
     ElseIf NumRounds <= 16 Then
         NumRounds = NumRounds - 6
     ElseIf NumRounds = 17 Then
         NumRounds = NumRounds - 7
     ElseIf NumRounds = 18 Then
         NumRounds = NumRounds - 8
     ElseIf NumRounds = 19 Then
         NumRounds = NumRounds - 9
     ElseIf NumRounds = 20 Then
         NumRounds = NumRounds - 10
     End If

     DiffTotal = 0
     For x = 1 To NumRounds
         DiffTotal = DiffTotal + CDbl(DiffArr(x-1))
     Next

     DiffAvg = DiffTotal/NumRounds


     HandicapTotal = FormatNumber(DiffAvg*.96,2)

     Response.Write "<div class=" & chr(34) & "breg" & chr(34) & " " & _
                    "style=" & chr(34) & "text-align:center;font-weight:bold;padding:3px;" & chr(34) & ">" & _
                    "Your Golf Handicap Index is " & HandicapTotal & _
                    "</div>"


  End If
%>

 <form name="GolfInfoForm" method="post" action="GolfHandicap.asp" onsubmit="return ValidateForm();">
 <table name="GolfInfoTbl" align="center" class="DataCell" cellspacing="0" style="background-color:#ffffff;">

 <thead>
 <tr>
 <td class="DataCellHead" title="Round Number">Round</td>
 <td class="DataCellHead" title="Your Score For The Round">Score</td>
 <td class="DataCellHead" title="The Course Rating">Rating</td>
 <td class="DataCellHead" title="The Slope Rating">Slope</td>
 <td class="DataCellHead">
         <input type="button" class="SubButton2" value="AddRow" onclick="moreFields();">
 </td>
 </tr>
 </thead>

 <tbody id="InfoRow" style="display:none;">
 <tr style="text-align:center;">
 <td class="DataCell"><input type="text" name="RoundNum" value="0" size="1" class="breg"></td>
 <td class="DataCell"><input type="text" name="Score" value="0" size="3" class="breg"></td>
 <td class="DataCell"><input type="text" name="Rating" value="0" size="3" class="breg"></td>
 <td class="DataCell"><input type="text" name="Slope" value="0" size="3" class="breg"></td>
 <td class="SubButton" onclick="this.parentNode.parentNode.removeChild(this.parentNode);ReNumber();">
     Remove
 </td>
 </tr>
 </tbody>

 <tfoot>
 <tr>
 <td colspan="5" class="DataCell" style="text-align:right;">
     <input type="submit" name="DoStuff" class="SubButton" value="Calculate Handicap">
 </tr>
 </tfoot>

 </table>
 </form>


<script language="JavaScript">

var counter = 0;
var TheForm = document.forms['GolfInfoForm'];
function moreFields()
{
  counter++;
  if(counter<20)
  {
    var newFields = document.getElementById("InfoRow").cloneNode(true);
    var insertHere = document.getElementById("InfoRow");
    newFields.id = "InfoRow" + counter;
  	newFields.style.display = "block";
    var newField = newFields.childNodes;
    insertHere.parentNode.insertBefore(newFields,insertHere);
  	TheForm.RoundNum[counter].value = counter;
  }
  ReNumber();
}

function ReNumber()
{
 for (var x=0;x<TheForm.RoundNum.length;x++)
   {
    TheForm.RoundNum[x].value = x;
    if(navigator.appName == "Microsoft Internet Explorer")
      {
       TheForm.RoundNum[x].value = x+1;
      }
     counter = x;
   }
}



<%
If Request("DoStuff") = "Calculate Handicap" Then

   For x = 0 to UBound(RoundNumArr)-1
      Response.Write "moreFields();" & chr(13)
      Response.Write "TheForm.RoundNum[" & x & "].value = " & x & ";" & chr(13)
      Response.Write "TheForm.Score[" & x & "].value = " & ScoreArr(x) & ";" & chr(13)
      Response.Write "TheForm.Rating[" & x & "].value = " & RatingArr(x) & ";" & chr(13)
      Response.Write "TheForm.Slope[" & x & "].value = " & SlopeArr(x) & ";" & chr(13)
   Next

   RoundNumArr = Split(Request("RoundNum"),",")
   ScoreArr = Split(Request("Score"),",")
   RatingArr = Split(Request("Rating"),",")
   SlopeArr = Split(Request("Slope"),",")
   NumRounds = UBound(RoundNumArr)
Else
      Response.Write "moreFields();" & chr(13)
End If
%>

function ValidateForm()
{
 var IsErr = false;
 var TheErr = "";
 var x = 1;
 var NumRows = TheForm.RoundNum.length;
 if(navigator.appName == "Microsoft Internet Explorer")
   {
    x = 0;
    NumRows = NumRows - 1
   }

  for (x=x;x<NumRows;x++)
   {
    var TheRowNum = x;
    if(navigator.appName == "Microsoft Internet Explorer")
      {
       TheRowNum = x+1
      }

    if (TheForm.Score[x].value.length == 0 || isNaN(TheForm.Score[x].value) == true)
     {
      IsErr = true;
      TheErr = TheErr + "\n\nPlease enter your score for round " + x;
     }
    else if (parseFloat(TheForm.Score[x].value) <= 0)
     {
      IsErr = true;
      TheErr = TheErr + "\n\nPlease enter your score for round " + x;
     }

    if (TheForm.Rating[x].value.length == 0 || isNaN(TheForm.Rating[x].value) == true)
     {
      IsErr = true;
      TheErr = TheErr + "\n\nPlease enter the course rating for round " + x;
     }
    else if (parseFloat(TheForm.Rating[x].value) <= 0)
     {
      IsErr = true;
      TheErr = TheErr + "\n\nPlease enter the course rating for round " + x;
     }
    if (TheForm.Slope[x].value.length == 0 || isNaN(TheForm.Slope[x].value) == true)
     {
      IsErr = true;
      TheErr = TheErr + "\n\nPlease enter the slope rating for round " + x;
     }
    else if (parseFloat(TheForm.Slope[x].value) <= 0)
     {
      IsErr = true;
      TheErr = TheErr + "\n\nPlease enter the slope rating for round " + x;
     }
   }

   if (IsErr == true)
   {
    alert(TheErr);
    return false;
   }
   else
   {
    TheForm.submit();
   }
}

</script>