This paper explores the domain of programming paradigm for Multi-Platform User Interfaces using XML based languages. The main focus of this work is User Interface Markup Language (UIML), an XML based language for describing user interfaces in a platform-independent manner. We have explored the capabilities of UIML as an interface description language for describing interactive websites. We have selected an end-user web programming tool called CLICK, which also uses an XML based interface description for the websites created through it. We have analyzed both the representations and devised a conversion process from CLICK XML to UIML. We have found that UIML is expressive enough to represent applications built using CLICK. UIML provides various benefits over the interface description generated by CLICK especially that of facilitating the development of web based interfaces for multiple platforms through CLICK.