function creation(tM, bM, lM, rM, unit) {
    if (app.documents.length == 0) {
        alert("ÇëÖÁÉÙ´ò¿ªÒ»¸öÎĵµ")
        return
    }

    // ͳһת»»Îªpt
    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")

    // »ñÈ¡µ±Ç°Ñ¡Öл­°å
    var arts = app.activeDocument.artboards // »­°å¼¯ºÏ
    var chooseArt = arts[arts.getActiveArtboardIndex()] // µ±Ç°Ñ¡ÖеĻ­°å
    var oldBounds = chooseArt.artboardRect
   
    try {
        chooseArt.artboardRect = [
            oldBounds[0] - leftMargin,
            oldBounds[1] + topMargin,
            oldBounds[2] + rightMargin,
            oldBounds[3] - bottomMargin,
        ]
    } catch (error) {
        alert("»­°å·¶Î§³¬³öÁËAI¹æ¶¨µÄ´óС")
    }
}

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