getting list separator from regional settings using firefox with javascript

Question

I am trying to get the list separator property which is configured in windows regional settings. I have found the below code which is working for IE and Chrome but unfortunately not working in firefox.

function getLocaleDelimeter(){

    var array = ['a', 'b'];
    var list_seperator = array.toLocaleString().substring(1, 2);
    var delimiter = ";";
    if (list_seperator != null && list_seperator != "")
    {
        delimiter = list_seperator;
    }

    return delimiter;

}

Could anyone tell me how to get the list seperator in firefox ? Thanks.