Generate random string in a html link

Generate random string in a html link

So I'm trying to make a link where the last part of the url is a random
string generated by JavaScript. The Javascript function I have been using
is this:
function randomString(length, chars) {
var result = '';
for (var i = length; i > 0; --i) result +=
chars[Math.round(Math.random() * (chars.length - 1))];
return result;
}
document.write(randomString(6,
'0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'));
How can I use this string inside a url, for example: <a
href="http://mypage.com/random-generated-string">?