function isIeForMac() {
    nua = navigator.userAgent.toLowerCase();
    if (nua.indexOf('msie') > -1 && nua.indexOf('mac') > -1) {
        return true;
    } else{
        return false;
    }
}
//version 1.1, uses document.write to ensure content gets refreshed.  Also makes sure popup receives focus on click
var popup_array = Array();
function open_popup(url, popup_name, options) {
	var cur_popup = popup_array[popup_name];
	var is_popup_defined = (typeof(cur_popup) == 'object');
	var is_popup_open = (is_popup_defined)
		? !(cur_popup.closed)
		: false;

	if ( is_popup_defined && is_popup_open ) {
		cur_popup.document.write (' ');
		cur_popup.focus();
		cur_popup.location.href = url;
		cur_popup.focus();
	} else if ((is_popup_defined && !is_popup_open) || !is_popup_defined) {
		popup_array[popup_name] = window.open(url, popup_name, options);
	}
}