Copy DIV content to another DIV

Assuming your selectors are correct, you should put your code in the .ready() Event.

http://api.jquery.com/ready/

So something like:

jQuery(document).ready(function() {
    jQuery('.buffer').html(jQuery("#beskeder_vis").html());
}

Otherwise jQuery won't be able to find your elements, since the DOM isn't loaded, when your function is executed.

You should bind event handler on ready event. See documentation: ready funciton

$(document).ready(function () {
  $('.buffer').html($("#beskeder_vis").html());
});
$('#two').html($('#one').html());

See this live example

It works for me. It may have something to do with the jquery version your using Proof jsfiddle