JQuery .Show() Doesn't Work With Server Control?

I have 2 html TR that i make them runat="server" & visible="false" and I have a dropdownlist called citiesDropDownList

$(document).ready(function() {
$('#<%=citiesDropDownList.ClientID %>').change(function() { ValidateCity(); });
});

and on change of this dropdownlist i check if the its text equal to a string i show the 2 tr as below

function ValidateCity() {
if ($('#<%= citiesDropDownList.ClientID %> :selected').text() == identity_CityOther) {
$('#<%= otherCityTR.ClientID %>').show();
$('#<%= areasTR.ClientID %>').show();
}
var city = $('#<%= citiesDropDownList.ClientID %>').val();
return IsValid((city.length != 0), '#<%= cityDiv.ClientID %>', identity_CityRequired);
}

.show() isn't work at all and i don't the reason .. can any lead me to get the problem?

FYI : I tried $('#<%= otherCityTR.ClientID %>').show('slow'); and also $('#<%= otherCityTR.ClientID %>').css('visibility', 'visible'); but it doesn't work also.