No, you can’t. The easiest way to make it work would be to put the function call directly after the element
Example:
...
<div id="somid">Some content</div>
<script type="text/javascript">
oQuickReply.swap('somid');
</script>
...
or – even better – just in front of </body>
:
...
<script type="text/javascript">
oQuickReply.swap('somid');
</script>
</body>
…so it doesn’t block the following content from loading.