function OpenWindow (sUri, iWidth, iHeight)
{
        var sWindowName = 'win' + Math.floor (Math.random() * 1000)
        var iRealWidth = iWidth ? iWidth : 600
        var iRealHeight = iHeight ? iHeight : screen.height - 300

        var iLeft = Math.round ((screen.width - iRealWidth) / 2)
        var iTop =  Math.round ((screen.height - iRealHeight) / 2) - 35

        var sWindowOptions = 'status=no,menubar=no,toolbar=no'
        sWindowOptions += ',resizable=yes,scrollbars=yes,location=no'
        sWindowOptions += ',width='  + iRealWidth
        sWindowOptions += ',height=' + iRealHeight
        sWindowOptions += ',left='   + iLeft
        sWindowOptions += ',top='    + iTop

        var win = window.open (sUri, sWindowName, sWindowOptions)
        win.focus()
}