var childWindowCallbackHandlers = {};

function acceptChildWindowCallback(callbackId, callbackData) {
    var handler = childWindowCallbackHandlers[callbackId];
    if (handler) {
        handler(callbackId, callbackData);
    }
}

function registerChildWindowCallbackHandler(callbackId, handler) {
    childWindowCallbackHandlers[callbackId] = handler;
}

function deregisterChildWindowCallbackHandler(callbackId) {
    childWindowCallbackHandlers[callbackId] = undefined;
}

function getDocumentElement(idOrName) {
    var e = document.getElementById(idOrName);
    if (!e) {
        e = document.getElementsByName(idOrName);
        if (e.length == 1) {
            e = e[0];
        }
    }
    return e;
}