Upon examining the page source, I noticed that it contains JavaScript code:
<script language="javascript" type="text/javascript">
styling += 'ul#topnav a.tabHeader5';
styling += '{';
styling += 'width: 142px;';
</script>
However, when I extract the HTML source using Selenium, the code changes to CSS:
<style type=\"text/css\">\n\t\t\t\tul#topnav a.tabHeader5\n\t\t\t\t{\n\t\t\t\t\twidth: 142px;</style>
I am puzzled as to why there is this conversion from JavaScript to CSS.