Javascript not updating in web browser?

I've got a code that basically calls today's date and adds two days to that date.  It basically makes an expiration date for a form.  

var d = new Date();
d.setDate(d.getDate()+2);
this.getField("Expires").value = "Expires" + util.printd("dd mmm yy", d);

The problem is that the script updates in Acrobat fine, but on Chrome/Edge that our company posts to, the script is defaulting to the date the file was posted.  Can this be fixed by changing the script or does the file always need to be downloaded for it to work?

Thanks.