var globalFeaturesForPopups = 'location=0 , statusbar=0 , menubar=0 , width=400 , height=400 ';

function popup(myLink, windowName, features)
{
    var href;
    var undef;
    if (features===undef) {
        features = globalFeaturesForPopups
    }
    if (windowName===undef) {
        windowName = '_blank';
    }
    if (typeof(myLink) == 'string')
       href=myLink;
    else
       href=myLink.href;
    var theWindow = window.open( href, windowName, features);
    theWindow.focus();
    return false;
}