Hi:
Generally drop down menus are part of an HTML form. The method that Patrick showed you for generating a button would be the same technique you'd use for generating a form. Conceptually, you'd need to develop the HTML form first before you coded it with SAS. You need to:
1) understand the HTML needed for an HTML form and a select box
2) understand what the form action should be
3) code the HTML form to contain a select box and test the form action when various selections are made.
for more information on HTML forms and select boxes, see:
http://www.w3schools.com/TAGS/tag_Select.asp
http://www.w3schools.com/TAGS/tag_form.asp
(Select box example from w3schools site)
[pre]
<select>
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
<option value="mercedes">Mercedes</option>
<option value="audi">Audi</option>
</select>
[/pre]
4) Once your "vanilla" HTML form is working, now you know how to code the DATA step program to generate the form with SAS. At this point, you could generate the select options from data set values (instead of hard-coding them for the test).
5) Now you have to deploy and implement your SAS program that generates the HTML form. How do you plan to invoke the SAS program? Where will the SAS program live? How do you intend for your users to receive the results from the use of the HTML form with the drop down box? What SAS products/configurations/installations are needed to make this form work??? If you have one SAS program that generates the form, what is the form action going to be that returns the results??? A second SAS program? Some other program?
Just a comment: this is the type of thing -- building an HTML form using SAS -- that is frequently done with the SAS/IntrNet product (and the Application Dispatcher or htmSQL) or with a Stored Process in the Information Delivery Portal.
cynthia