/*
Used for the spreadsheet like functionality of SSA's size
calculator.

*/

function update(name)
{
        sizeField = "s_" + name;
        size = eval("document.forms[0]." + sizeField + ".value");

        qtyField = "q_" + name;
        qty = eval("document.forms[0]." + qtyField + ".value");

        totalField = "t_" + name;

        // Check up on the qty field to check that it is a number
        if (!isInteger(qty))
        {
                alert ("You must enter a number for the quantity");

                eval("document.forms[0]." + totalField + ".value = 0");
        }
        else
        {
                totalSize = qty * size;

                totalSize = roundOff(totalSize, 2);

                eval("document.forms[0]." + totalField + ".value = " + totalSize);

                updateGrandTotal();
        }
}


function updateGrandTotal()
{
        numberTotals = document.forms[0].elements.length;
        grandTotal = 0;

        for (i = 0; i < numberTotals; i++)
        {
                if (document.forms[0].elements[i].name.substr(0,2) == "t_")
                {
                        grandTotal += eval(document.forms[0].elements[i].value);
                }
        }

        grandTotal = roundOff(grandTotal, 2);
        document.forms[0].total.value = grandTotal;

}


function getIndex(input)
{
        var index = -1, i = 0, found = false;
        while (i < input.form.length && index == -1)
        {
                if (input.form[i] == input)
                {
                        index = i;
                }
                else
                {
                        i++;
                }
        }
        return index;
}


function nextFocus(element)
{
        formIndex = (getIndex(element) + 2) % element.form.length;
        element.form[formIndex].focus();
}


//-------------------------------------------------------------------
// isInteger(value)
//   Returns true if value contains all digits
//-------------------------------------------------------------------
function isInteger(val) {
        for (var i=0; i < val.length; i++) {
                if (!isDigit(val.charAt(i))) { return false; }
                }
        return true;
        }

//-------------------------------------------------------------------
// isDigit(value)
//   Returns true if value is a 1-character digit
//-------------------------------------------------------------------
function isDigit(num) {
        var string="1234567890";
        if (string.indexOf(num) != -1) {
                return true;
                }
        return false;
        }


function roundOff(value, precision)
{
        value = "" + value //convert value to string
        precision = parseInt(precision);

        var whole = "" + Math.round(value * Math.pow(10, precision));

        var decPoint = whole.length - precision;

        result = whole.substring(0, decPoint);
        result += ".";
        result += whole.substring(decPoint, whole.length);

        return result;
}