Implementing context-sensitive help requires cooperation between the help author and the developer of the application that displays the context-sensitive help topics. You both need a mapping .jhm file that associates topic IDs with the target URL. When an application calls a context-sensitive help topic, it uses the topic ID to display the correct topic. Therefore, both the help and the application must use the same mapping file. If the topic IDs and target URLs do not match, the application displays either the wrong topic or no topic.

The mapping .jhm file lists topic IDs and target URLs. This mapping file is also referred to as a header file. For Oracle Help and Sun JavaHelp, the mapping file is similar to the following sample file:

<mapID target="ch1_htm_999374" url="ch1.htm#999374">

<mapID target="ch2_htm_999640" url="ch2.htm#999640">

<mapID target="ch9_htm_999786" url="ch9.htm#999786">

In this example, ch1_htm_99374 is a topic ID, and ch1.htm#99374 is the target URL for this particular topic ID. The marker in the appropriate topic has the ch1_htm_999374 value.

When you implement context-sensitive help, you need to work with your application developers to decide how to choose the topic ID for each context-sensitive help topic. You can choose a set of topic IDs and embed them in your source documents using TopicAlias markers. When you generate output, ePublisher generates a mapping file using those topic IDs and assigns the target URL to each topic ID based on your source documents. You can provide the generated mapping file to your application developers, who can embed the topic IDs in the application code. ePublisher generates an updated file each time you generate the help. Remember to give the updated file to your application developers each time.