function get_by_id(id) {
    var d = null;
    if (document.getElementById) d = document.getElementById(id);
    if (!d && document.all) d = document.all[id];
    if (!d && document.layers) d = document.layers[id];
    return d;
}
function enable(id) {
    var d = get_by_id(id);
    if (d) d.disabled = undefined;
}
function disable(id) {
    var d = get_by_id(id);
    if (d) d.disabled = 'disabled';
}
function hide(id) {
    var d = get_by_id(id);
    if (d) d.style.display = 'none';
}
function focus(id) {
    var d = get_by_id(id);
    if (d) d.focus();
}
function show(id) {
    var d = get_by_id(id);
    if (d) d.style.display = 'inline';
}

function trim(str, charlist) {
    charlist = !charlist ? ' \r\n\s\xA0' : charlist.replace(/([\[\]\(\)\.\?\/\*\{\}\+\$\^\:])/g, '\$1');
    var re = new RegExp('^[' + charlist + ']+|[' + charlist + ']+$', 'g');
    return str.replace(re, '');
}

function ktrim(s) {
    var rx = new RegExp("^[\\s\\n\\r]*(.*)[\\s\\n\\r]*$", "m");
    rx.exec(s); return RegExp.$1;
}

function is_empty(s) { return !s || trim(s) == ''; }
function go(url) {
    document.location.href = url;
}