Question

<a id="link" href="http://www.google.co.uk">link</a>

<a id="link" href="http://stackoverflow.com">link</a>

the javascript only replaces the first href but i want it to apply to any and all <a> with the id="link" OR do you have a jQuery alternative?

<script>
var link = document.getElementById('link');
var src = link.getAttribute('href');
var paramurl = encodeURIComponent(src);
link.setAttribute("href", "http://mysite.com/?url=" + paramurl);
</script>

Answer 1

Use a class-name instead of an id:

<a class="link" href="http://www.google.co.uk">link</a>

<a class="link" href="http://stackoverflow.com">link</a>

With the JavaScript:

var links = document.getElementsByClassName('link');
for (i=0;i<links.length;i++){
    var src = links[i].getAttribute('href');
    var paramurl = encodeURIComponent(src);
    links[i].setAttribute('href','http://mysite.com/?url=' + paramurl);
    /* or, preferably:
    links[i].href = 'http://mysite.com/?url=' + paramurl;
    */
}

JS Fiddle demo.