AddThis code don't work in asp.net 4.0
<p>I copied and paste <strong>AddThis</strong> code to a <strong>.aspx</strong>,  but when I run the <strong>.aspx</strong>, I get error. why? Thanks!</p>

<pre><code>Warning 1   Validation (XHTML 1.0 Transitional): This attribute name must be followed by an equal (=) sign and a value. If the value is in quotation marks, the quotation marks must match. 
C:\Users\CW\Documents\Visual Studio 2010\WebSites\WebSite5\Default.aspx 16  44  C:\...\WebSite5\
</code></pre>



<pre><code>&lt;%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %&gt;

&lt;!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"&gt;

&lt;html xmlns="http://www.w3.org/1999/xhtml"&gt;
&lt;head runat="server"&gt;
    &lt;title&gt;&lt;/title&gt;
&lt;/head&gt;
&lt;body&gt;
    &lt;form id="form1" runat="server"&gt;

    &lt;div&gt;

    &lt;!-- AddThis Button BEGIN --&gt;
&lt;div class="addthis_toolbox addthis_default_style "&gt;
&lt;a class="addthis_button_facebook_like" fb:like:layout="button_count"&gt;&lt;/a&gt;
&lt;a class="addthis_button_tweet"&gt;&lt;/a&gt;
&lt;a class="addthis_button_google_plusone" g:plusone:size="medium"&gt;&lt;/a&gt;
&lt;a class="addthis_counter addthis_pill_style"&gt;&lt;/a&gt;
&lt;/div&gt;
&lt;script type="text/javascript" src="http://s7.addthis.com/js/250/addthis_widget.js#pubid=mycwcgr"&gt;&lt;/script&gt;
&lt;!-- AddThis Button END --&gt;

    &lt;/div&gt;
    &lt;/form&gt;
&lt;/body&gt;
&lt;/html&gt;
</code></pre>
