Difference between IE 10 rendered HTML and its out

Question

I use IE 10 F12 button to locate a < a > node on my page, I got this:

<a tabindex="-1" class="level1 static" href="About.aspx">About</a>

But I use the following code to retrieve the page HTML, and get this:

<a class="level1" href="About.aspx">About</a>

Code:

        WebClient wc = new WebClient();
        String pageString = wc.DownloadString(url);

Why are they different?

Update:

Below is the Fiddler monitor result.

IE10:

WebClient:

Answer 1

This question is duplicated with this one: How to get the page source from an IE window?

And I have solved it there.

Answer 2

It's typical for webservers to send different output depending on which browser the request is coming from. Perhaps this "simplified" <a> tag is a result of that?

I'm not sure how WebClient works but perhaps it's possible to modify headers so you can act like you're an IE10 browser and see if the results are different.