Security for Cross-script
By default, Flash Player dose not allow swfA.swf to script swfB.swf because of the diffrent domains. A SWF file gives permittion to SWF files from other domains by calling Security.allowDomain() method. For example shown below, swfA.swf can script swfB.swf, but swfB.swf cannot script swfA.swf. You can set up symmetrical permissions by having both SWFfiles call the Security.allowDomain() method.
swfA.swf
loader.load(new URLRequest("http://siteB.com/swfB.swf")); loader.content.init();
swfB.swf
Security.allowDomain("siteA.com"); function init(){...};