var objWindow;

function openWindow(strURL, 
                    strWindowName, 
                    intWidth, 
                    intHeight, 
                    boolCenteredOnPage)
{
    if (strWindowName == null ||
        strWindowName == "")
    {
        alert("You must provide a window name");
    }
    else if (strWindowName.indexOf(" ") != -1)
    {
        alert("Spaces cannot be included in the window name");
    }
    else
    {
        if (boolCenteredOnPage)
        {
            intLeft = (window.screen.width / 2) - ((intWidth / 2) + 10);
            intTop = (window.screen.height / 2) - ((intHeight / 2) + 30);
        }
        else
        {
            intLeft = 0;
            intTop = 0;
        }
            
        if (objWindow != null &&
            !objWindow.closed)
        {
            objWindow.close();
        }

        objWindow = window.open(strURL, strWindowName, "width=" + intWidth + ",height=" + intHeight + ",left=" + intLeft + ",top=" + intTop + ",screenX=" + intLeft + ",screenY=" + intTop + ", toolbar=0, location=0, directories=0, status=0, menubar=0, scrollbars=0, resizable=0");
    }
}