[smearf man]

You can put JavaScript right inside of the AS3 as follows:

import flash.external.*;

var JStodo:XML = 
<script>
<![CDATA[
function (marg) {

function dothis(forarg)
{
alert(forarg);
};

dothis(marg);

//the function in dothis can be any function defined in the wrapper

}
]]>
</script>;

//calling the script
if (ExternalInterface.available) 
{ExternalInterface.call(JStodo);}

hope this helps