IE, Dom Access In A HTMLDocument ?!

I think, it's very simple to do, but i don't know how ?!
i've got a html page which contains :

<div id="myDiv">
<hr />
<hr />
<hr />
<hr />
</div>

And in a javascript (client side), i want to access to the dom model of the
div :
i wan't to be able to use selectnodes on "myDiv" :
be able to do something like that :

var myDiv = document.GetElementById("myDiv");
var xmlDoc = myDiv.implementation ; // to obtain dom of mydiv ?!
var nodeList = xmlDoc.selectNodes("hr") ;

is it possible with "microsoft internet explorer" ? (it works on gecko based
browsers)