PHP 'include' function

Hi. I have just discovered server side scripting and am trying to get to grips with it using PHP4 with Xitami on Windows Me. Straight away, on my first project, it looks as though I have found a problem I am not going to solve without help. I have an HTML form with an Option Select drop down list which displays choices of which JPEG file to load into an <IMG> picturebox. After selecting an option, clicking a button runs a Javascript function which displays the image, changing the previous picture. So far so good, but here is the problem. I also wish to display a caption and descriptive paragraph or two in an adjacent scrollable <TEXTAREA>. I thought a good way would be to have a text file for each picture on the server and display the appropriate one as required. But, so far, I have not managed to find any file operation capabilities in Javascript. My next thought was to use the PHP "include" function, or some other file reading technique, but I have not found a satisfactory way to pass the filename to PHP. A Javascript variable naturally cannot be passed to a PHP function so I had Javascript copy the file pathname to the TextArea with the hope of getting my include function to pick it up from there. But I have not succeeded. PHP does not like the dots in "$captionpath = Document.FormName.TextAreaName.Value;" and simply removes them. So I abandoned this and tried doing it completely outside of Javascript. I have tried everything I can think of including a rigmarole which involved the self-submit method <FORM METHOD="POST" ACTION="<?php print('$php_self'); ?>">. Without going into detail, I did manage to display the caption but I had other problems which made this avenue seem unproductive, so I did not persue it. For example, instead of just a clean change of the IMG and TextArea contents the whole page was reloaded from the server and repositioned at "Top of Page". Apart from the slowness of this, it looked massively clumsy. Am I missing the obvious?? Regards John Morrison