I have website built by html5 and served by Apache, I have installed Nodejs on the same sever.
I want to use node mail to send email each time a html page visited, how can I make the html page to trigger a Nodejs file/program or module?
I just don't know how the HTML page can interact with Nodejs program on the server
You can use Ajax technology.
Using ajax, you can request an http request trigger your node server to do mail delievery.
Kit
Nodejs is a server side technology. How would you have done it using PHP or Rails? It's the same in principle.
You could for example expose a REST API to call into the server and send a mail, which could then be called from the javascript on the client.
Apache and Node run as two different servers and two different processes.
As described by others, you could use client-side ajax to trigger actions between the two servers. You could use something like dnode that provides RPC (remote procedure calls) between two servers. As described on https://github.com/substack/dnode There are dnode implementations for perl, ruby, php, and java, so you can glue together all your backend processes swimmingly.
On the same server you could create a new process. For instance, using PHP you could use system or popen to call node. ie. system("node mail.js [args]"). Make sure to escape your arguments carefully. Here is a popen example: http://svn.php.net/viewvc/pear/packages/Mail/trunk/Mail/sendmail.php?view=markup
Note: I am not sure what advantages using node mail has over using the standard implementation in your apache stack (ie. using PHPjust call mail()). If you are looking for non-blocking there are options available in most cases: Send mail without blocking 'execution'
