Deprecated This feature has been removed from the Web standards. Though some browsers may still support it, it is in the process of being dropped. Do not use it in old or new projects. Pages or Web apps using it may break at any time.
This chapter describes methods in the plug-in API that are provided by the browser; these allow call back to the browser to request information, tell the browser to repaint part of the window, and so forth. The names of all of these methods begin with NPN_ to indicate that they are implemented by the browser and called by the plug-in. For an overview of how these two sides of the plug-in API interact, see the How Plug-ins Work and Overview of Plug-in Structure sections in the introduction.
Warning: You must only call these from the main thread; calling them from other threads is not supported and may have unpredictable results.
Allows a plugin to change the stored information associated with a URL, in particular its cookies. (While the API theoretically allows the preferred proxy for a given URL to be changed, doing so does not have much meaning given how proxies are configured, and is not supported.)