Embedding *.swf objects: javascript vs xhtml [closed]

I am a newbie in webdesign and I´ve been wondering which is the modern way to embed swf objects.

I've been using the following html code:

<object id="flash1" data="presentacion/prototipe.swf" height="300" type="application/x-shockwave-flash" width="500">
<param name="movie" value="presentacion/prototipe.swf" />
</object>

However, I've noticed that some designers use a javascript to embed swf files. Like this one

<script type="text/javascript">
var flashvars = {
};

var params = {
    menu: "false",
    scale: "noScale",
    allowFullscreen: "true",
    allowScriptAccess: "always",
    allowNetworking: "all",
    bgcolor: "#ffffff",
    base: "swf/"
};
var attributes = {
    id:"flashMovie"
};
swfobject.embedSWF("swf/flash_movie.swf", "flashMovie", "550", "400", "9.0.0", "swf/expressinstall.swf", flashvars, params, attributes);
</script>

It seems that both ways produce the same results but: what are the shorfalls of these methods? which method is the newest ? Are there any compatibility issues regarding the web-browsers?

Thanks in advance.

I've posted this question in stack-overflow too. I don't know exactly where this question should be posted.