function myFunction(param){
  argumentArray = new Array;
  argumentArray = param.split(",");
  for (i=0; i< argumentArray.length; ++i){
    trace("Function argument " + i + " = " + argumentArray[i]);
  }
}

http://kb.adobe.com/selfservice/viewContent.do?externalId=tn_15639&sliceId=2

to call this function you would use "asfunction:myFunction,argument1,argument2,argument3" as the href in the  tag in an HTML text box.

Using asfunction to trigger actionscript from a URL link.

url, actionscript, link, function

ActionScript