In Adobe Illustrator, How to change white color of Edittext to transparent with javascript when it is active

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I want to change white color to transparent when the edittext is active.
Please help me.

w.alignChildren = ["fill","fill"];
w.preferredSize = [150, 250];
w.inputBox = w.add('panel', undefined, "Input Box");

w.inputBox.add('statictext{text: "Height: "}');

var heightInput = w.inputBox.add('edittext {characters: 12, active: true}');

w.inputBox.add('statictext{text: "Width: "}');

var widthInput = w.inputBox.add('edittext {characters: 12, active: false}');

w.inputBox.add('statictext{text: "Spine: "}');

var spineInput = w.inputBox.add('edittext {characters: 12, active: false}');

w.inputBox.add('statictext{text: "Joint: "}');

var jointInput = w.inputBox.add('edittext {characters: 12, active: false}');

var okBtn = w.add("button", undefined, "Draw");