A simple web Script to read different Mysql databases

Would like a PHP programming that would read and search different databases from MySQL , or all databases together. name of database and fields would be in an XML files. a list of all databases names, and common fields would be in in a separate XML (in case the user selected to search all databases) This webpage would use java-script, PHP 7.x
The webpage would list all databases (from XML file) for user to select one or all to Search.
(Extra: a PHP web-script to list all the search result from the above, note all databases include a filed (filename to view an images