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()

    return win
}