SO fiddle

Test Fiddle mainly for SO Questions

by Nick Craver

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.4/themes/overcast/jquery-ui.css">
<input id="address_nations_id" value="105" type="text" />

JavaScript

if($.inArray($('#address_nations_id').val(), ["105", "74"]) > -1) {
    alert("found");
}