Domain Relaxing 

If you are implementing JavaScript with inter-frame communication or inter-window communication, note the special features of domain relaxing.

A document’s domain is usually determined using the host’s domain:

document.domain=host.domain

For example, the domain specification for the host and document can be as follows:
ls0028.wdf.sap.corp

Since the portal host is not usually the same as the BSP host (the portal web server does not have to be identical with the BSP application server), the principle of domain relaxing is used.

Domain relaxing involves deleting the host name data that is listed before the first period in domains.

For example, with domain relaxing the following domain data are summarized:
pgwdf.wdf.sap.corp
ls0028.wdf.sap.corp
This results in wdf.sap.corp

Domain relaxing is carried out for all pages and frames that communicate with each other.

Domain relaxing can be implemented using a tiny piece of JavaScript, inserted in the coding before a different frame is called for the first time, such as:

var liBehindFirstDot = location.hostname.indexOf( "." ) + 1;   if (liBehindFirstDot > 0) {     document.domain = location.hostname.substr( liBehindFirstDot );   }

Maximum Relaxing

The type of domain relaxing described above can lead to problems in applications where communication passes through several frames. For example, the first frame is to be filled by pwdf1234.wdf.sap.corp and the second by pwdf6789.phl.sap.corp.

With the standard domain relaxing the phl.sap.corp domain gets deleted. This means, however, that the two frames cannot communicate together.

There is a new domain relaxing mode to remedy such cases, where the domain is reduced to a minimum size. The domain is made smaller and smaller until the browser raises an objection. In the example above, both sap.corp domains are reduced in size.

The URL parameter for this situation is: sap-domainRelax = off | min | max

System-specific URL Parameters describes the additional URL parameters that were predefined.