function creation(tM, bM, lM, rM, unit) {
    if (app.documents.length == 0) {
        alert("Ո���ٴ��_һ���ęn")
        return
    }

    // �y(t��ng)һ�D�Q��pt
    var topMargin = UnitValue(tM, unit).as("pt")
    var bottomMargin = UnitValue(bM, unit).as("pt")
    var leftMargin = UnitValue(lM, unit).as("pt")
    var rightMargin = UnitValue(rM, unit).as("pt")

    // �@ȡ��ǰ�x�Ю���
    var arts = app.activeDocument.artboards // ���弯��
    var chooseArt = arts[arts.getActiveArtboardIndex()] // ��ǰ�x�еĮ���
    var oldBounds = chooseArt.artboardRect
   
    try {
        chooseArt.artboardRect = [
            oldBounds[0] - leftMargin,
            oldBounds[1] + topMargin,
            oldBounds[2] + rightMargin,
            oldBounds[3] - bottomMargin,
        ]
    } catch (error) {
        alert("���巶��������AIҎ(gu��)���Ĵ�С")
    }
}

creation(1, 1, 1, 1, "m")