innerHTML Isn't working in Firefox and IE
<p>I have a feeling that I'm missing something simple here but can't seem to find it.</p>

<p>I'm using SwfUpload and on its <code>uploadSuccess()</code> event, I'm showing a "success" message on the screen while hiding the progress image.  Below is the snippet:</p>

<pre><code>swfu.uploadSuccess = function(file, serverData, response) {
    document.getElementById("progressImg").display = "none";

    var uploadMessage = document.getElementById("UploadMessage");
    uploadMessage.style.display = "block";
    uploadMessage.innerHTML("The file, " + file.name + ", was uploaded successfully.");     
};
</code></pre>

<p>Everything works fine up until the last line when I'm attempting to set the text of the <code>uploadMessage</code> object.  The object refers to a <code>&lt;span&gt;</code> tag though I've also tried it as a <code>&lt;div&gt;</code> just in case.  IE8 says that <code>innerHTML</code> is not supported and FF3.5.4 doesn't show any errors (haven't added firebug yet).  I've also tried to just put set static text instead of a concatenated string to no avail either.</p>

<p>This is a trivial task that I've done countless times w/ and w/o a framework; however, it's not working at this time.  What am I missing?</p>

<p>Thanks</p>

<p>EDIT:</p>

<p>Since someone may wonder, current doctype is set to HTML 4.0 Transitional.</p>
