The following is a quick and simple example of embedding the XAP as an object in a web page.  Since this is Silverlight 5-based, you will need to ensure you have the correct version of Silverlight installed.

<div id="silverlightControlHost">
    <object data="data:application/x-silverlight-2," 
       type="application/x-silverlight-2" width="100%" height="100%">
        <param name="source" value="QBRatingSL.xap" />
        <param name="onError" value="onSilverlightError" />
        <param name="background" value="white" />
        <param name="minRuntimeVersion" value="5.0.61118.0" />
        <param name="autoUpgrade" value="true" />
        <a href="http://go.microsoft.com/fwlink/?LinkID=149156&v=5.0.61118.0" 
           style="text-decoration:none">
            <img src="http://go.microsoft.com/fwlink/?LinkId=161376" 
                 alt="Get Microsoft Silverlight" style="border-style:none"/>
        </a>
    </object>
    <iframe id="_sl_historyFrame" style="visibility:hidden; height:0px; 
       width:0px; border:0px"></iframe>
</div>