Question

This works on all browser except IE9, getAttribute return null on IE9, any ideas

function getFlashMovieObject(movieName){
    if(document.embeds[movieName])
      return document.embeds[movieName];
    if(window.document[movieName])
      return window.document[movieName];
    if(window[movieName])
      return window[movieName];
    if(document[movieName])
      return document[movieName];
}

function ChangePlaylist(newval,mymovievarmp3){
    var mp3Player = getFlashMovieObject(mymovievarmp3);
    var newstring = mp3Player.getAttribute('data');
    var broken = new Array();
    broken = newstring.split('?');
    mp3Player.setAttribute('data',broken[0]+'?'+broken[1]+'?'+newval)
}

Using JQuery but still does not work

    var mp3Player = getFlashMovieObject(mymovievarmp3);
    var newstring = $("#mp3Player ").data("data");

Answer 1

Try the following code:

 function ChangePlaylist(newval,mymovievarmp3){
     var mp3Player = getFlashMovieObject(mymovievarmp3);
     //previus declaration
     //var newstring = mp3Player.attributes['data'].nodeValue;

     //Although i'm not familiar with getFlashMoiveObject, if that function
     //a reference to the javascript object, the next should work fine. 
     var newstring = $(mp3Player).attr('data');

     //If that does not work, then try adding an `id`, or a `class` to the object
     //and then do one of the next:

     //using `id`:
     //var newstring = $('#mp3PlayerId').attr('data');


     //using `class`:
     //var newstring = $('.mp3PlayerClass').attr('data');

     //Also note that `id` and `class` are standard attributes, and so they values can
     //be accessed using regular getAttribute.

     var broken = new Array();
     broken = newstring.split('?');
     //mp3Player.setAttribute('data',broken[0]+'?'+broken[1]+'?'+newval)

     //Update - To set the a value to data attribute:
     $(mp3Player).attr('data',broken[0]+'?'+broken[1]+'?'+newval);
 }

IE have issues getting non standard attributes from elements.

Update:

If you are willing to use another library such as jQuery you can easily do something like

  $('#elementId').attr('data');

And is going to be crossbrowser for sure.

Update 2

I updated the code and explained a bit. Hope it helps you out!

Update 3

The following code can be used to set value to data:

     $(mp3Player).attr('data',value);