property width

This property sets and gets the width of the box. Note: For boxes that are fixed position, width can be specified in pixel coordinates, percentage (of parent), or with the "auto" keyword. For flowed boxes, percentage units are not supported and are interepreted as pixel dimensions.

function GetBoxWidth()
{
    var bx = scene.getBoxById("myBox");
    if (bx)
    {
        shell.print ("width: " + bx.width);
    }
}