Bootstrap modal window issue loading external resources in internet explorer

Question

I am trying to load external resources like website, pdf file using Bootstrap modal window but it does not works for IE, it works fine in Chrome and firefox,

HTML

 <img src="images/ajax-loader.gif" id="loading-indicator" style="display:none"/>

   <a class="btn btn-primary btn-lg external" data-toggle="modal" href="https://www.taxsimple.com" data-target="#myModal">Load WebSite</a>

   <a class="btn btn-primary btn-lg external" data-toggle="modal" href="http://www.irs.gov/pub/irs-pdf/f1098t.pdf" data-target="#myModal">Load PDF</a>

   <a class="btn btn-primary btn-lg external" data-toggle="modal" href="https://help.taxsimple.com/identity-protection-pin/" data-target="#myModal">taxsimple help</a>

<!-- Modal -->
<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
  <div class="modal-dialog">
    <div class="modal-content">
  <div class="modal-body">
      <iframe class="modal-body" id="frame1">Browser Doestn support iframe</iframe>
  </div>
  </div><!-- /.modal-content -->
  </div><!-- /.modal-dialog -->
</div><!-- /.modal -->

Style

    .modal-dialog
    {
        width:80%;height:100%;
    }
    .modal-content
    {
        height:100%;
    }
    .modal-body
    {
        width:100%;height:100%;
    }

    #loading-indicator
    {
        position: absolute;
        left: 500px;
        top: 500px;
    }

Script

    $(document).ready(function() {
        $('a.external').on('click', function (e) {
            $('#loading-indicator').show();
            e.preventDefault();
            var url = $(this).attr('href');
            $('#frame1').attr('src', url);
        });

        $('#myModal').on('shown.bs.modal', function () {
            $('#loading-indicator').hide();
        });
 })

has anyone faced such issue, any help will be appreciated.

EDIT:

In case of IE, error gets thrown from script block

 [dynamic] file -- 'stLight' is undefined
 stLight.options ({publisher: "39544329-cc80-4c4f-a204-3ef09bf3e9a2"});