We are sending page url value from Tealium for a page, in some conditions we need to override this value for child page (in a page there is a section driven from Ajax & Modal page), how to override this vale for modal/ajax section if we generate a virtual url, currently it is taking parent page url (from Tealium).
It sounds like you are tracking an ajax modal as a pageview which makse sense.
We track ajax modals as events. So when a user is on a page and opens a modal, we trigger a modal event and pass a modal name. That way we can track what modals are being opened across the site and from which pages without increasing pageview count. In this case we don't need to override the url.
One of the Tealium folks would have better insight on this but this approach may work.
To overwrite your url (I think this would depend on how your virtual url us being stored). If it is being stored in a variable you could use a set values extension.
Set url = to Variable = "your virtual url value"
when condition = "your condition"
or maybe you could set the url to some JS code that grabs our virtual url and replaces the dom.url .
I would say Jim nailed it. Once you know the variable you use to populate the URL attribute you would set up you extension as Jim has outlined.
Let's say you use "page_url" as the url variable and the url that you need to override is "www.manish.com/modal/page"
Your extension would be as follows:
Set page_url To: Text <"new url value">
Condition url equals "www.manish.com/modal/page"
You can use a different option instead of Text, but that is the simplest option for this example.