By default it uses this format, and I don't think it allows you to select otherwise.
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta name="Generator" content="iWeb 2.0.4" />
<meta name="iWeb-Build" content="local-build-20081007" />
<meta name="viewport" content="width=700" />
<title>Tom’s Photography</title>
<link rel="stylesheet" type="text/css" media="screen,print" href="moviemovei_files/moviemovei.css" />
<!--[if IE]><link rel='stylesheet' type='text/css' media='screen,print' href='moviemovei_files/moviemoveiIE.css'/><![endif]-->
<script type="text/javascript" src="Scripts/iWebSite.js"></script>
<script type="text/javascript" src="Scripts/Widgets/SharedResources/WidgetCommon.js"></script>
<script type="text/javascript" src="Scripts/Widgets/Navbar/navbar.js"></script>
<script type="text/javascript" src="Scripts/iWebImage.js"></script>
<script type="text/javascript" src="moviemovei_files/moviemovei.js"></script>
</head>
<body style="background: #ffffff url(moviemovei_files/Creme_browserbg.jpg) repeat scroll top left; margin: 0pt; " onload="onPageLoad();" onunload="onPageUnload();">
<div style="text-align: center; ">
<div style="margin-bottom: 20px; margin-left: auto; margin-right: auto; margin-top: 20px; overflow: hidden; position: relative; word-wrap: break-word; text-align: left; width: 700px; " id="body_content">
<div style="background: transparent url(moviemovei_files/LayeredPaper_03-1.jpg) repeat scroll top left; width: 700px; ">
<div style="height: 73px; margin-left: 0px; position: relative; width: 700px; z-index: 5; " id="header_layer">
<div style="height: 0px; line-height: 0px; " class="bumper"> </div>
<div style="height: 248px; width: 700px; height: 248px; left: 0px; position: absolute; top: 0px; width: 700px; z-index: 1; " class="tinyText style_SkipStroke">
<img src="moviemovei_files/LayeredPaper_01.jpg" alt="" style="border: none; height: 248px; width: 700px; " />
</div>
<div style="height: 41px; width: 626px; height: 38px; left: 20px; position: absolute; top: 35px; width: 625px; z-index: 1; " class="tinyText style_SkipStrokeSkipFillSkipOpacity">
<div style="position: relative; width: 625px; ">
<img src="moviemovei_files/shapeimage_1.png" alt="" style="height: 36px; left: 0px; margin-left: -1px; margin-top: 5px; position: absolute; top: 0px; width: 272px; " />
</div>
</div>
</div>
<div style="margin-left: 0px; position: relative; width: 700px; z-index: 10; " id="nav_layer">
<div style="height: 0px; line-height: 0px; " class="bumper"> </div>
<div style="height: 1px; line-height: 1px; " class="tinyText"> </div>
<div class="com-apple-iweb-widget-navbar flowDefining" id="widget0" style="margin-left: 20px; margin-top: -1px; position: relative; width: 625px; z-index: 1; ">
<div id="widget0-navbar" class="navbar">
<div id="widget0-bg" class="navbar-bg">
<ul id="widget0-navbar-list" class="navbar-list">
<li></li>
</ul>
</div>
</div>
</div>
<script type="text/javascript"><!--//--><![CDATA[//><!--
new NavBar('widget0', 'Scripts/Widgets/Navbar', 'Scripts/Widgets/SharedResources', '.', {"current-page-GUID": "93A786AF-EC42-40C5-9D6E-F6602E9E1321", "path-to-root": "", "isCollectionPage": "NO", "navbar-css": ".navbar {\n\tfont-family: 'Hoefler Text', 'Times New Roman', serif;\n\tfont-size: .9em;\n\tcolor: #817B67;\n\tmargin: 0px;\n\tline-height: 25px;\n}\n\n.navbar-bg {\n\ttext-align: left;\n}\n\n.navbar-bg ul {\n\tlist-style: none;\n\tmargin: 0px;\n\tpadding: 0px;\n}\n\n\nli {\n\tlist-style-type: none;\n\tdisplay: inline;\n\tpadding: 0 25px 0 0px;\n}\n\n\nli a {\n\ttext-decoration: none;\n\tpadding: 0px;\n\tcolor: #817B67;\n}\n\nli a:visited {\n\ttext-decoration: none;\n\tpadding: 0px;\n\tcolor: #817B67;\n}\n\nli a:hover\r{\r\n \tcolor: #3F3F3C;\n\ttext-decoration: none;\r}\n\n\nli.current-page a\r{\r\t color: #3F3F3C;\n\ttext-decoration: none;\r}"});
//--><!]]></script>
<div style="clear: both; height: 0px; line-height: 0px; " class="spacer"> </div>
</div>
<div style="margin-left: 0px; position: relative; width: 700px; z-index: 15; " id="body_layer">
<div style="height: 0px; line-height: 0px; " class="bumper"> </div>
<div style="height: 301px; width: 545px; height: 266px; left: 70px; position: absolute; top: 33px; width: 525px; z-index: 1; " class="tinyText style_SkipStrokeSkipFillSkipOpacity_1 shadow_0">
<div style="position: relative; width: 525px; ">
<img src="moviemovei_files/shapeimage_2.png" alt="" style="height: 301px; left: 0px; margin-left: -10px; margin-top: -15px; position: absolute; top: 0px; width: 545px; " />
</div>
</div>
<script type="text/javascript"><!--
writeMovie1();
--></script>
<div style="height: 1px; line-height: 1px; " class="tinyText"> </div>
<div style="margin-left: 20px; margin-top: 357px; position: relative; width: 625px; z-index: 1; " class="style_SkipStroke_1 flowDefining">
<div class="text-content Normal_External_625_100" style="padding: 0px; ">
<div class="Normal">
<p style="padding-bottom: 0pt; padding-top: 0pt; " class="Body">THIS IS A TEXT BOX WHERE A LOT OF MY CONTENT GOES.</p>
</div>
<div style="height: 32px; line-height: 32px; " class="tinyText"> </div>
</div>
</div>
<div id="id2" style="height: 25px; left: 20px; position: absolute; top: 333px; width: 625px; z-index: 1; " class="style_SkipStroke_2">
<div class="text-content Normal_External_625_25" style="padding: 0px; ">
<div class="Normal">
<p style="padding-bottom: 0pt; padding-top: 0pt; " class="Title">My Movie</p>
</div>
</div>
</div>
<div id="id3" style="height: 256px; left: 410px; position: absolute; top: 37px; width: 175px; z-index: 1; " class="style_SkipStroke_3">
<div class="text-content style_External_175_256" style="padding: 0px; ">
<div class="style">
<p style="padding-bottom: 0pt; padding-top: 0pt; " class="Quote">SOME MORE TEXT IN THIS BOX</p>
</div>
</div>
</div>
<div style="height: 22px; line-height: 22px; " class="spacer"> </div>
</div>
<div style="height: 120px; margin-left: 0px; position: relative; width: 700px; z-index: 0; " id="footer_layer">
<div style="height: 0px; line-height: 0px; " class="bumper"> </div>
<div style="height: 236px; width: 700px; height: 236px; left: 0px; position: absolute; top: -116px; width: 700px; z-index: 1; " class="tinyText style_SkipStroke">
<img src="moviemovei_files/LayeredPaper_04.jpg" alt="" style="border: none; height: 236px; width: 700px; " />
</div>
<a href="http://www.me.com" title="http://www.me.com"><img src="moviemovei_files/mwmac_white.png" alt="Made on a Mac" style="border: none; height: 50px; left: 263px; opacity: 0.70; position: absolute; top: 60px; width: 139px; z-index: 1; " id="id4" />
</a>
</div>
</div>
</div>
</div>
</body>
</html>
Like a lot of wysiwyg editors it is setup to make it easy to add RSS feeds, blogposts, photosharing and quicktime so that a user can easily share their media and such. And the pages do validate.
