In recent years, more and more programs have been designed to operate using a web based user interface.  Such interfaces appear and operate as World Wide Web (“WWW” or the “Web”) pages.  While the applications provide the look and feel of a web interface, the actual program may reside on a remote computer connected via the Web, or locally on the user's computer. 
As the web based interface has grown in popularity, the complexity of such interfaces has grown.  In the beginning of the web, each web page was a single entity and every element of the page was stored in a single HTML document.  As web development progressed, pages were broken up into separate components using frames or web parts.  Such development greatly expanded the usability of web pages and allows web based programs to resemble typical non-web based programs. 
One advance in the development of web pages is the use of web parts.  Web parts represent a “part” of a web page.  Such “parts” may include specialized applications which run independently within a web page.  Web parts are typically separately compiled programs, referred to as web part assemblies, which are called and inserted into a page.  If a web developer wishes to modify the web part, a programmer typically must modify and recompile the web part assembly.  Alternatively, the web developer may insert customized HTML commands into a web page which operate to modify or add to the web part.  Such additional HTML code must be reentered or copied into every other web page which calls that web part, if similar changes to the web part are desired on other web pages.  Even then, if a change is made to this additional code, it must now be replicated in each page that includes the additional code. 
Accordingly, a problem in the prior art is that a web part assembly can not be customized, simply and easily, without the need for recompiling. 
Another problem in the prior art is that a customized web part assembly utilized in multiple instances cannot be modified without changing each instance of use of the web part assembly. 
Another problem in the prior art is that, if separate commands are provided, they must be inserted into each web page which calls the web part assembly.