how i pass arguments opposite functions javascript?

i'm perplexing figure out pass arguments an opposite duty javascript.

check out illustration formula i cruise i mean:

<input type="button" value="click me" id="mybutton" />

<script type="text/javascript">
    var mybutton = document.getelementbyid("mybutton");
    var mymessage = "it's working";
    mybutton.onclick = function(mymessage) { alert(mymessage); };
</script>

when clicking symbol message: it's working should appear. however mymessage non-static inside opposite duty null.

jquery uses lot opposite functions, best proceed pass argument?