ActionScript 2.0 Language Reference - Adobe Help and Support

Occasionally, you might encounter the following situation. Suppose you load a child SWF file
from a different domain. You want to implement this method so that the child SWF file can
make LocalConnection calls to the parent SWF file, but you don't know the final domain
from which the child SWF file will come. This can happen, for example, when you use loadbalancing
redirects or third-party servers.
In this situation, you can use the MovieClip._url property in your implementation of this
method. For example, if you load a SWF file into my_mc, you can then implement this
method by checking whether the domain argument matches the domain of my_mc._url.
(You must parse the domain out of the full URL contained in my_mc._url.)
If you do this, make sure that you wait until the SWF file in my_mc is loaded, because the _url
property will not have its final, correct value until the file is completely loaded. The best way
to determine when a child SWF file finishes loading is to use
MovieClipLoader.onLoadComplete.
The opposite situation can also occur: You might create a child SWF file that wants to accept
LocalConnection calls from its parent but doesn't know the domain of its parent. In this
situation, implement this method by checking whether the domain argument matches the
domain of _parent._url. Again, you must parse the domain out of the full URL from
_parent._url. In this situation, you don't have to wait for the parent SWF file to load; the
parent will already be loaded by the time the child loads.
Availability: ActionScript 1.0; Flash Player 7
Parameters
sendingDomain:String [optional] - A string that specifies the domain of the SWF file that
contains the sending LocalConnection object.
Example
The following example shows how a LocalConnection object in a receiving SWF file can
permit SWF files from any domain to invoke its methods. Compare this to the example in
LocalConnection.connect(), in which only SWF files from the same domain can invoke
the trace() method in the receiving SWF file. For a discussion of the use of the underscore
(_) in the connection name, see LocalConnection.send().
this.createTextField("welcome_txt", this.getNextHighestDepth(), 10, 10,
100, 20);
var my_lc:LocalConnection = new LocalConnection();
my_lc.allowDomain = function(sendingDomain:String) {
domain_txt.text = sendingDomain;
return true;
};
724 ActionScript classes