Adding Word Processing to Webapplication

For a new webapplication I need word processing capabilities. More projects will follow on this subject, but as a start, I need a simple page with only one button: "Start word processor". When the user clicks on this button a word processor is launched (I am open for advice which word processor is to be used). After the user created his document, he can save the document. The document? must be? saved on the webserver. It can be saved as a file on the webserver or it can be inserted in a MySQL table. (I want to be advised on this matter, what are the pros and cons of both methods?). So to summerize: 1. Create a page with one button to launch a word processor. 2. When the users clicks on "Save", the document is saved at the webserver (Linux system). How the document is saved (seperate file or into MySQL database), it's up to you. After a successful implementation of this project, more projects will be posted to fully integrate word processing into the bigger webapplication.