Question: I have to support IE8. The modal itself works fine, but my attempts to resize it (which work fine in Firefox) don't work in IE8.

I'm just adding a class (wide-modal in this example) to the modal-dialog div (the 2nd nested one in the Bootstrap structure) and applying a width via CSS, nothing fancy.

HTML:

```
       <div class="modal fade" id="modalTest" role="dialog">
            <div class="modal-dialog wide-modal">
              <div class="modal-content ">
                <div class="modal-header">
                  <button type="button" class="close" data-dismiss="modal" aria-hidden="true">&times;</button>
                  <h4 class="modal-title">Testing Modal</h4>
                </div>
                <div class="modal-body">
                  <img src="content/Example-Infographic.jpg" width="100%" />
                </div>
                <div class="modal-footer">
                  <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
                </div>
              </div><!-- /.modal-content -->
            </div><!-- /.modal-dialog -->
        </div>

```

CSS:

```
.wide-modal {
    width: 60%;
}

```

I tried adding the class to the div above and below to no (positive) effect. It works like a charm where it is in Firefox, just no effect at all in IE8. I also tried with a px width, no difference. I do have the respond.js library in place so in general IE8 is behaving other than this.

Answer: 
I know it is late but just found in [bs3 docs](http://getbootstrap.com/javascript/#modals) you can add `modal-lg` class to your modals

```
<!-- Large modal -->
<button class="btn btn-primary" data-toggle="modal" data-target=".bs-example-modal-lg">
  Large modal
</button>

<div class="modal fade bs-example-modal-lg" tabindex="-1" role="dialog" aria-labelledby="myLargeModalLabel" aria-hidden="true">
  <div class="modal-dialog modal-lg">
    <div class="modal-content">
     ...
    </div>
  </div>
</div>

<!-- Small modal -->
<button class="btn btn-primary" data-toggle="modal" data-target=".bs-example-modal-sm">
  Small modal
</button>

<div class="modal fade bs-example-modal-sm" tabindex="-1" role="dialog" aria-labelledby="mySmallModalLabel" aria-hidden="true">
 <div class="modal-dialog modal-sm">
   <div class="modal-content">
     ...
   </div>
 </div>
</div>

```
This will of course change the width for all of your modal windows, but it might give you a better idea on how this works. I just changed my modal windows this way. 

```
    .modal-body {
        position: relative;
        padding: 20px;
        min-width: 800px; /* SET THE WIDTH OF THE MODAL */
    }

    .modal-content {
        position: relative;
        background-color: #fff;
        border: 1px solid #999;
        border: 1px solid rgba(0,0,0,0.2);
        border-radius: 6px;
        outline: 0;
        -webkit-box-shadow: 0 3px 9px rgba(0,0,0,0.5);
        box-shadow: 0 3px 9px rgba(0,0,0,0.5);
        background-clip: padding-box;
        width: 900px; /* SET THE WIDTH OF THE MODAL */
        margin: 50px 0 0 -150px; /* CHANGE MARGINS TO ACCOMMODATE THE NEW WIDTH */
    }

<!-- Button trigger modal -->
  <a data-toggle="modal" href="#myModal" class="btn btn-primary btn-lg">Launch demo modal</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-header">
          <button type="button" class="close" data-dismiss="modal" aria-hidden="true">&times;</button>
          <h4 class="modal-title">Modal title</h4>
        </div>
        <div class="modal-body">
          ...
        </div>
        <div class="modal-footer">
          <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
          <button type="button" class="btn btn-primary">Save changes</button>
        </div>
      </div><!-- /.modal-content -->
    </div><!-- /.modal-dialog -->
  </div><!-- /.modal -->

```