function getQueryVariable(variable) {
    var query = window.location.search.substring(1);
    var vars = query.split("&");
    for (var i = 0; i < vars.length; i++) {
        var pair = vars[i].split("=");
        if (pair[0] == variable) {
            return pair[1];
        }
    }
}

var size;
size = getQueryVariable("fs");
if (size != null && size != "") {
    size = size.toString();
    switch (size) {
        case "normal":
            document.getElementById("norm_fs").src = "/new/images_structure/norm_fs_active.gif";
            document.getElementById("medium_fs").src = "/new/images_structure/medium_fs.gif";
            document.getElementById("large_fs").src = "/new/images_structure/large_fs.gif";
            break;

        case "medium":
            document.getElementById("norm_fs").src = "/new/images_structure/norm_fs.gif";
            document.getElementById("medium_fs").src = "/new/images_structure/medium_fs_active.gif";
            document.getElementById("large_fs").src = "/new/images_structure/large_fs.gif";
            break;

        case "large":
            document.getElementById("norm_fs").src = "/new/images_structure/norm_fs.gif";
            document.getElementById("medium_fs").src = "/new/images_structure/medium_fs.gif";
            document.getElementById("large_fs").src = "/new/images_structure/large_fs_active.gif";
            break;
    }
}