for ie9 does support xhr headers

withoutxhr

var $note_html = $(data);
if($note_html.hasClass('user_prospects_note')) {
    $('#prospectsEmptyNotes').remove();         //if this is first note, delete empty node.                    
    if($('#'+$note_html.attr('id')).length == 0) {
        $('#user_prospects_notes .sp-container').prepend(data);
    } else {
        $('#'+$note_html.attr('id')).replaceWith(data);
    }
    $('#as-modal').modal('hide');
} else {
    $("#as-modal").html(data);
}

withxhr

if(xhr.getResponseHeader('blockId') != null) {
    $('#prospectsEmptyNotes').remove();         //if this is first note, delete empty node.
    if($(xhr.getResponseHeader('blockId')).length == 0) {
        $('#user_prospects_notes .sp-container').prepend(data);
    } else {
        $(xhr.getResponseHeader('blockId')).replaceWith(data);
    }
    $('#as-modal').modal('hide');
} else {
    $("#as-modal").html(data);
}