Without jQuery, you can access the <h1>'s textContent property (innerText in old IE), and you can change document.title (like modifying the <title></title>). Here's an example:
var text = "textContent" in document.body ? "textContent" : "innerText";
document.title = document.getElementsByTagName("h1")[0][text];
Depending on how you want to target the <h1>, you can change the document.getElementsByTagName("h1")[0].
Also, I'm not sure how it affects the title, but the whitespace before the first <a> and after the last </a> will be included unless you trim the string. So maybe turn it into:
function trim(s) {
if (typeof s === "string") {
s = s.replace(/^\s+|\s+$/g, "");
}
return s;
}
var el = document.getElementsByTagName("h1")[0],
text = "textContent" in el ? "textContent" : "innerText";
document.title = trim(el[text]);
DEMO: http://jsfiddle.net/tzGzC/
Of course, with just jQuery, it's a lot simpler:
var el = $("h1").eq(0),
text = el.text();
document.title = $.trim(text);
DEMO: http://jsfiddle.net/kMXLW/
References: