adobe acrobat form texbox value direction

I need a script to change the textbox value direction to right to left or left to right as the language in the  dropdown list i used the script below and the alignment worked useful but the direction is not working:

// Get the language from a dropdown or text field
var language = this.getField("lang").value;

// Get the text field
var textField = this.getField("Textbox");

// Set the direction based on the language
if (language === "ARABIC") {
textField.alignment = "right";
textField.direction = "rtl"; // right-to-left
} else if (language === "ENGLISH") {
textField.alignment = "left";
textField.direction = "ltr"; // left-to-right
}