<button id="start">Start</button>
<button id="reset">Reset</button>
<input id="counter" value="233"/>

JavaScript的

$(function ()
{
    var $start = $('#start'),start = $start.get(0),$reset = $('#reset'),reset = $reset.get(0),$counter = $('#counter'),startVal = $counter.text(),currentVal = startVal,endVal = 250,prefix = '$',fontSize = $counter.css('font-size');

    $start.click(function ()
    {
        this.disabled = true;
        var i = setInterval(function ()
        {
            if (currentVal === endVal)
            {
                clearInterval(i);
                reset.disabled = false;
                $counter.animate({fontSize: fontSize});
            }
            else
            {
                currentVal++;
                $counter.text(prefix+currentVal).animate({fontSize: '+=1'},100);
            }
        },100);
    });

    $reset.click(function ()
    {
        $counter.text(prefix + startVal);
        this.disabled = true;
        start.disabled = false;
    }).click();
});

Demo →