validate a dropdownbox by jquery

I try to validation a form by jquery , the following method work on text field

[code]
var add3=$(“#address_Three”);
var add3Info=$(“#addoneinfo3”);

function validateAdd3(){
if( add3.val()==’#’ ){
add3.addClass(“error”);
add3Info.text(“Address, Please”);
add3Info.addClass(“error”);
return false;
}
else{
add3.removeClass(“error”);
add3Info.empty();
add3Info.removeClass(“error”);
return true;
}
}

<select name=”address_Three” id=”address_Three”><span id=”addoneinfo3″></span>
<option selected value=”#”>—Please select—</option>
<option selected value=”1″>1</option>
<option selected value=”2″>2</option>[/code]

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