Actually your approach is better to see whitespaces and linebreaks directly inside the browser, since the XML view in FF doesn't show it.

FWIW here a nodelet hack which opens a JS.alert() with the HTML of the post you are trying to reply to.

<script><!--
function show_quote() {
alert(document.querySelector("div.preview").innerHTML.match(/^[^]*?(?=
+<hr> <div class="editnodetext">)/)[0]);
}
--></script>

<a href='javascript:show_quote()'> show_quote</a>
[download]

(you need to be in a "comment on" node to make it work)

it was part of my plans to extend my wiki-syntax with comfortable quoting of a users post...

... of course milking the XML-displaytype would be more reasonable here.