Do you want it in javascript? Since you didn't put PHP in your tags, I would assume so.
In that case, you can use window.location.href
to do it in javascript.
document.getElementById("share-button-1").setAttribute("data-link", window.location.href);
or in jquery:
$('#share-button-1').attr("data-link", window.location.href);
in case you did mean through PHP, you could use the following:
http://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]
. In this case I'd use it like this:
<?php
$dataUrl = "http://".$_SERVER[HTTP_HOST].$_SERVER[REQUEST_URI];
?>
<a class="toggle-tell-friend" id='share-button-1' rel="sidebar" data-id='share-content-1' data-title='<?php echo CHtml::decode($job->getTitle());?>' data-link="$dataUrl">Friend</a>