Mantener el valor de un select

[America|UNK]

Hay 3 formas:

Con JavaScript (uso de Cookies o localStorage):

Código Javascript:

var val = window.localStorage && typeof localStorage["elValor"] != "undefined" ? localStorage["elValor"] : "valorDefecto";
 
$("#select").val(val).change(function(){ localStorage["elValor"] = $(this).val()})
 

Con HTML a través del formulario con parámetros GET y JavaScript:

Código Javascript:

function getParameterByName(name) {
    //http://stackoverflow.com/questions/901115/how-can-i-get-query-string-values-in-javascript
    name = name.replace(/[\[]/, "\\[").replace(/[\]]/, "\\]");
    var regex = new RegExp("[\\?&]" + name + "=([^&#]*)"),
        results = regex.exec(location.search);
    return results == null ? "" : decodeURIComponent(results[1].replace(/\+/g, " "));
}
 
 
$("#select").val(getParameterByName("selectValor"));
 

Código HTML:

<form method="get" action="./">
<select name="selectValor" id="select"></select>
 

Con PHP.