purdal calculator

<div>
<div style="float:right; padding: 0 1em; font-size: x-small; color: grey;">Version 0.7</div>
<!-- Wolf Peuker 2013-07-09 -->
<script type="text/javascript">
//<![CDATA[

function MultipleCharsBy(ch, count)
{
        var result = ch;
        for (var i=1; i<count; ++i)
                result += ch;
        return result;
}

function format(f, digs, width)
{
        if (typeof digs == 'undefined') digs=3;
        if (typeof width == 'undefined') width=1;
        var vorkomma = width -1 -digs;
    var space = MultipleCharsBy('#', width);
    var zeros = MultipleCharsBy('0', digs);
        var factor = Math.round(Math.pow(10, digs));
    var zahl = String(Math.floor((f*factor)+0.5)/factor);
    var kpos = zahl.indexOf('.');
    if (kpos == -1) { 
                if (digs > 0) {
                        kpos = zahl.length;
                        zahl += '.0';
                }
    }
    zahl = space.substring(0, vorkomma-kpos)+zahl;
    zahl = zahl+zeros.substring(0, width-zahl.length);
    zahl = zahl.replace(/#/g, "&nbsp;");
    return zahl;
}

function purdals(opart)
{
    return 9900.0*opart;
}

function cents(opart)
{
    return 1200.0*opart;
}

function millioctaves(opart)
{
    return 1000.0*opart;
}

function convert()
{
    var inputval = document.getElementById("number").value;
        var notation = "Unknown notation";
    var text = '';
    var val = '';
        var fval
    if (inputval.match(/^\s*\d+(\.\d*)?\s*$/) || inputval.match(/^\s*\.\d+?$\s*/)) {
                notation = "Decimal notation";
        val = parseFloat(inputval.match(/(\S+)/));
    } else {
                var rval = inputval.match(/^\s*(\d+)\s*\/\s*(\d+)\s*$/);
                if (rval) {
                        notation = "Fractional notation";
                        if (rval.length == 3) {
                                var num = parseInt(rval[1]);
                                var den = parseInt(rval[2]);
                                if (den != 0) {
                                        if (num != 0) {
                                                val = 1.0*num/den;
                                        } else {
                                                text += "Error: numerator must be a positive number.\n <br/>";
                                        }
                                } else {
                                        text += "Error: denominator must be a positive number.\n <br/>";
                                        val = num;
                                }
                        }
                } else {
                        var pval = inputval.match(/^\s*(\d+)\s*\\\s*(\d+)\s*$/);
                        if (pval) {
                                notation = "EDO degree notation";
                                if (pval.length == 3) {
                                        var num = parseInt(pval[1]);
                                        var den = parseInt(pval[2]);
                                        if (den != 0) {
                                                e = num/den;
                                                val = Math.pow(2, e);
                                        } else {
                                                text += "Error: denominator must be a positive number.\n <br/>";
                                                val = num;
                                        }
                                }
                        } else {
                                var gval = inputval.match(/^\s*(\d+)\s*\\\s*(\d+)\s*[Ee][Dd]\s*(\d+)\s*$/);
                                if (gval) {
                                        notation = "Generic ED* degree notation";
                                        if (gval.length == 4) {
                                                var num = parseInt(gval[1]);
                                                var den = parseInt(gval[2]);
                                                var ed = parseInt(gval[3]);
                                                if (ed > 0) {
                                                        if (den != 0) {
                                                                e = num/den;
                                                                val = Math.pow(ed, e);
                                                        } else {
                                                                text += "Error: denominator must be a positive number.\n <br/>";
                                                                val = num;
                                                        }
                                                } else {
                                                        text += "Error: ed must be followed by a positive number. <br/>";
                                                }
                                        }
                                }
                        }
                }
        }
    
        function mkRef(addr, text) {
            var prefix = "http://xenharmonic.wikispaces.com/";
                return '<a href="'+prefix+addr+'">'+text+'<\/a>';
        }
    // var lval = Math.log(val)/log(2);
        text += notation+" <br/>";
        var result = "???";
        if (val != '') {
            if (val == 0.0) {
                        result = "zero ???";
                }
                var lval = Math.log(val)/Math.log(2);
        var digits = document.getElementById("precision").selectedIndex;
                result = format(purdals(lval), digits);
                text += "Decimal value: "+format(val, 8)+" <br/>"
                text += "Log2: "+format(lval, 8)+" <br/>"
                text += mkRef("Cent","Cents")+": "+format(cents(lval), digits+2)+" <br/>";
                text += mkRef("Millioctave","Millioctaves")+": "+format(millioctaves(lval), digits+2)+" <br/>";
                text += mkRef("Microtone","Microtones (µt)")+": "+format(lval*5884949.1923617, 0);
        } else {
                text = "Unknown Notation";
        }
        document.getElementById("result").innerHTML = "Purdals: "+result;
        document.getElementById("details").innerHTML = text;
}
//]]>
</script>
<div style="border: 1px black; padding: 1em; background-color: #d9d8ed;"><img style="float:right;" src="http://purdal.wikispaces.com/file/view/g3803.png/438779918/g3803.png" /> <b>Please input an expression for the interval.</b><br />
<small>These notations are currently supported:</small>
<ul>
<li><small>Fractional: 3/2, 7 /6, 5/ 6</small></li>
<li><small>EDO degrees: 7\12, 1\ 17, 3 \17</small></li>
<li><small>Generic ED* degrees: 7\19 ed 3, 11\19 ED2, 11\53ed7</small></li>
<li><small>Decimal: 1, 1.5, 0.7, .9</small></li>
</ul>
<div style="float:right;">precision: <select id="precision" name="precision" onclick="convert()">
<option value="0">0</option>
<option value="1" selected="selected">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
</select> (decimal digits)</div>
<p><input id="number" name="number" value="3/2" onchange="convert()" /><input type="button" value="Go!" onclick="convert()" /></p>
<big><span id="result">results</span></big><br />
<div id="details" style=" border: gray solid 1px; background-color: #eee; font-family: monospace; font-size: smaller; margin: 1em 0; padding: 1em 1em">details</div>
</div>
</div>