page number and header using batch header javascript

hello,

I am trying to create a script using java for my batch header processing. I currently have a script that was given a while back but need it updated, the problem is I don't know who wrote it and I know nothing about it.

I need it formatted to show the page number in the middle (center of page) with the file name on the top right hand side of the pdf, can anyone help?

/* Top right hand corner */

/* Get the filename and trim off
the '.PDF' */

var filename = this.documentFileName

filename = Left(filename,
String(filename).length);

/* Get Start Time */

var d1 = new Date();

var pages = this.pageNum + ' of  ' + this.numPages;

1. this.addWatermarkFromText(

{

                cText:pages,

                nFontSize: 8,

                nTextAlign:
app.constants.align.center,

                nHorizAlign:
app.constants.align.center,

                nVertAlign:
app.constants.align.top,

                nHorizValue: -4, nVertValue:
-4,

                bOnTop: true,

                bOnScreen: true,

                bOnPrint: true,

                aColor:color.black

                });

this.addWatermarkFromText(

{

                cText:filename,

                nFontSize: 8,

                nTextAlign: app.constants.align.center,

                nHorizAlign:
app.constants.align.right,

                nVertAlign:
app.constants.align.top,

                nHorizValue: -4, nVertValue:
-4,

                bOnTop: true,

                bOnScreen: true,

                bOnPrint: true,

                aColor:color.black

                });

function Left(str, n)

{

  
if (n<=0)

        return "";

  
else if (n > String(str).length)

        return str;

  
else

        return String(str).substring(0,22);

}

not sure if this is even right at the moment, but I need one for my headers to be aligned centered for page numbers and top right side for file name.

any help is greatly appreciated.