Timing test for Javascript

HTML

<h1>Javascript timing test</h1>
<p>See the console.  Note the difference between the Firefox console and Firebug's console, and a run with no console open.</p>
<p>Note: this page takes about 10 seconds to run.</p>

CSS

table, th, td {
    margin: 1em;
    padding: 0.2ex 1ex;
}
th {
    text-align: right;
}

JavaScript

var numMeasurements = 100;
var measurementList = [];
var startDate       = new Date ();
var startTime       = startDate.getTime ();

console.log (
    startDate.getHours ()+ " : " + startDate.getMinutes () + " : "
    + startDate.getSeconds () + " : " + startDate.getMilliseconds ()
);

var startDate   = new Date ();  //-- Record time just before interval start.
//setTimeout (timelog, 100);
var logTimer    = setInterval (timelog, 100);

function timelog () {
    timelog.numloops    = timelog.numloops  ||  0;

    if (timelog.numloops >= numMeasurements) {
        console.log ('===> Reached ' + timelog.numloops + ' loops.');
        clearInterval (logTimer);

        //--- Calculate stats:
        var stats           = {};
        stats.min           = Number.MAX_VALUE; //-- Always start at opposite
        stats.max           = Number.MIN_VALUE;
        stats.sum           = 0;
        stats.mean          = 0;
        stats.sumSqrs       = 0;
        stats.stdDev        = 0;
        stats.N             = measurementList.length;

        for (var J = 0;  J < stats.N;  ++J) {
            var measVal     = measurementList[J];
            stats.sum      += measVal;
            stats.sumSqrs  += measVal * measVal;

            if (measVal > stats.max)    stats.max = measVal;
            if (measVal < stats.min)    stats.min = measVal;
        }

        stats.mean          = stats.sum / stats.N;
        stats.stdDev        = Math.sqrt (
            (stats.sumSqrs / stats.N) - (stats.mean * stats.mean)
        );


        //--- Display stats:
        var decsToDisplay   = 2;
        console.log (' Measurements: ' + stats.N);
        console.log ('      Average: ' + stats.mean.toFixed (decsToDisplay) );
        console.log ('   Min to Max: ' + stats.min + ' to ' + stats.max);
        console.log ('Std Deviation: ' + stats.stdDev.toFixed (decsToDisplay) );
        
        $("body").append (
            '<table>'
            + '    <tr>'
            + '       ...