ExternalInterface.call("changeTitle");

<script language="JavaScript">
function changeTitle(title) {
if(title == undefined) {
title = "New Title";
}
window.title = title;
}
</script> 

ExternalInterface.call("changeTitle", "ActionScript 3.0 Cookbook");

var title:String = ExternalInterface.call("getTitle");

<script language="JavaScript">
function getTitle( ) {
return window.title;
}
</script> 

var request:URLRequest = new URLRequest("javascript:alert('example');");
navigateToURL(request);