A unified web-based voice messaging system provides voice application control between a web browser and an application server via an hypertext transport protocol (HTTP) connection on an Internet Protocol (IP) network. The application server executes the voice-enabled web application by runtime execution of a first set of extensible markup language (XML) documents that define the voice-enabled web application to be executed. The application server generates an HTML form specifying selected application parameters from an XML document executable by the voice application. The HTML form is supplied to a browser, enabling a user of the browser to input or modify application parameters for the corresponding XML document into the form. The application server inserts the received input application parameters into the XML document, and stores the document.