var ho new Date var hours ho getHours function thisday var hr select n

var ho = new Date();
var hours = ho.getHours() + 1;
function thisday(h){
    var hr = "<select name=\"time\">";
    for(var i=h;i<=22;i++){
        hr += "<option value=\"" + i + "\">" + i + "</option>";
    }
    hr += "</select>";
    return hr;
}
function nextday(){
    var hr = "<select name=\"time\">";
    for(var i=9;i<=22;i++){
        hr += "<option value=\"" + i + "\">" + i + "</option>";
    }
    hr += "</select>";
    return hr;
}
function nextday2(){
    var hr = "<select name=\"time\">";
    for(var i=9;i<=22;i++){
        hr += "<option value=\"" + i + "\">" + i + "</option>";
    }
    hr += "</select>";
    return hr;
}
jQuery
$(document).ready(function(){
$("#thisday").click(function(){
        $("#hours").html(thisday(hours));
    });
    $("#nextday").click(function(){
        $("#hours").html(nextday());
    });
    $("#nextday2").click(function(){
        $("#hours").html(nextday2());
    });
});
HTML
<tr>
<td>День:</td>
<td><select name="day"><option value="сегодня" id="thisday">Сегодня</option><option value="завтра" id="nextday">Завтра</option><option value="послезавтра" id="nextday2">Послезавтра</option></select></td>
</tr>
<tr>
<td>Время:</td>
<td id="hours"><script language="javascript" type="text/javascript">$("#hours").html(thisday(hours));</script></td>
</tr>