Preview PDF di Modal Bootstrap dengan Ajax

//preview pdf in line
function preview_surat_keputusan(no)
{
$('#form')[0].reset();
$('.form-group').removeClass('has-error');
$('.help-block').empty();

$.ajax({
url : "<?php echo site_url('surat_keputusan/ajax_preview/')?>/" + no,
type: "GET",
dataType: "JSON",
    success: function(data)
    {
    //paramater yang akan ditampilkan di modal
        $('[name="no"]').val(data.no);
        $('[name="ns"]').val(data.ns);
        $('[name="thts"]').val(data.thts);
        $('[name="pdf"]').val("http://localhost/dosdm/document/sm/pdf/"+data.thts+"-SK-"+data.ns+".pdf");
        var link_base =  "http://localhost/dosdm/document/sm/pdf/"+data.thts+"-SK-"+data.ns+".pdf" ;
            $('#pdf_view').attr('src', link_base);
                   

            //bereksperimen
        $('#modal_form_1').modal('show');
        $('.modal-title').text('preview_surat_keputusan');
    //-----   
    },
error: function (jqXHR, textStatus, errorThrown)
{
alert('Error get data from ajax');
}
});
}

function reload_table()
{
table.ajax.reload(null,false);
}


//==========================//


Modal:





<!-- Bootstrap modal -->
<div class="modal fade" id="modal_form_1" role="dialog">
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span></button>
        <h3 class="modal-title"></h3>
</div>

<div class="form-group">
<label class="control-label col-md-3">Nama File</label>
<div class="col-md-9">
<input name="pdf" class="form-control" type="text">
<span class="help-block"></span>
</div>
<div style="text-align: center;">
    <iframe  class="form-control" src="" id="pdf_view" style="width:100%; height:500px;" frameborder="0"></iframe>
</div>       
</div>
</div>
<div class="modal-footer">
</div>
</div><!-- /.modal-content -->
</div><!-- /.modal-dialog -->
</div><!-- /.modal -->
===


ajax di control"

====
public function ajax_preview($no)
{
$data = $this->sk->get_by_id($no);
echo json_encode($data);
}