function PostToNewWindow() {
    var originalTarget = document.forms[0].target;    // Note the var!
    document.forms[0].target = '_blank';
    window.setTimeout(function() {                    // Use a function with setTimeout,
        document.forms[0].target = originalTarget;    // not least so it has access to
    }, 600);                                          // local vars like `originalTarget`.
    return true;
}