how i can add this external script to the template

i will lik to add the next external script for chat help live...

<script type="text/javascript">
var LHCChatOptions = {};
LHCChatOptions.opt = {widget_height:340,widget_width:300,popup_height:520,popup_width:500,domain:'systrabajo.com'};
(function() {
var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true;
var referrer = (document.referrer) ? encodeURIComponent(document.referrer.substr(document.referrer.indexOf('://')+1)) : '';
var location = (document.location) ? encodeURIComponent(window.location.href.substring(window.location.protocol.length)) : '';
po.src = 'http://chat.systrabajo.com/index.php/esp/chat/getstatus/(click)/internal/(position)/bottom_right/(ma)/br/(top)/350/(units)/pixels/(leaveamessage)/true/(department)/1/(survey)/1?r='+referrer+'&l='+location;
var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s);
})();
</script>


how i can do this please?

Thanks ,

Hi

Copy it at the end of /layout/blocks/head.php