Help with Dropdownbox and following problems

Question

Hello BWler.
I think my post is rather a crazy idea, but I hope you can bring me on the right track! 
My question: Is that generally feasible with HTML and Javascript or with other tools.
I hope you understand my English.
I would like to create a document (not the web item) in Web Application Designer which contains values from different Queries. It has three parts, Header, Body and Rest. The Header of the document can contain three different data (either material or customer or vendor), for which individual queries was defined. The Body gets data from an other query. The Rest is only text.
This is my idea, but I don’t know, if it’s a good solution.
In the first step I would like to fill a Dropdownbox with the three options of the Header (not on a characteristic in a query). The user selects a value and press the "submit" button.. Depending on which value was selected, the suitable Query and a defined characteristic should be used in the next Dropdownbox.
That’s my attempt to fill my own dropdonbox an display the selected value. The URL looks right, but not the result ;-). The choice suitable dropdownbox was not implemented yet.
customer
material
vendor
Question: How can this be solved to join own and WAD dropdownboxes?
Now if the right dropdownbox  is displayd, the values should be filtered. But e.g. for customer I have many values, therefore I’d like to create a nested dropdown menu. The first column should contain the letters “a” to “z”. After selection the values begins with this letter (e.g. all customers with letter “t”) should be read from the Query and then shown in the dropdownbox.
Question: Is that generally possible and if so, what one must define in addition in query designer?
Finally the result of the filtering should be displayed as text…

Answer 1

@ Raja
Thx for your reply. I will try it maybe later with BSP. Maybe I can also use java.
@ Deepak
Thx for your example. Now my first problem is solved. However, I have some more questions.
DDB=Dropdownbox
DP=DataProvider
First:
1) Is it possible to fill my own values in a BW-DDB without characteristic from query?
Second:
2) Is it possible to change only the DP for the same DDB.
I would like to use the same DDB, either with the values of product or customer or vendor, if I change the value of my own DDB.
My current solution is to change one DP with the right values.
<option value="<SAP_BW_URL ITEM='DDB_ITEM_1' HIDDEN='' CMD_1="DATA_PROVIDER=DATAPROVIDER_2&CMD=RESET_DATA_PROVIDER&INFOCUBE=ZPRODUCT&QUERY=ZPR" IOBJNM='PRODUCT'>"> product</option>
But my hope is to change only the DP(DATAPOVIDER1=customer, DATAPOVIDER2=vendor, DATAPOVIDER3=product) for the same DDB.
So I test it ... but I receive only the DDB with a value (" All"):
<object>
         <param name="OWNER" value="SAP_BW"/>
         <param name="CMD" value="SET_DATA_PROVIDER"/>
         <param name="NAME" value="DATAPROVIDER_2"/>
         <param name="QUERY" value="ZVEND"/>
         <param name="INFOCUBE" value="ZVENDOR"/>
         DATA_PROVIDER:             DATAPROVIDER_2
</object>
<object>
         <param name="OWNER" value="SAP_BW"/>
         <param name="CMD" value="SET_DATA_PROVIDER"/>
         <param name="NAME" value="DATAPROVIDER_3"/>
         <param name="QUERY" value="ZPR"/>
         <param name="INFOCUBE" value="ZPRODUCT"/>
         DATA_PROVIDER:             DATAPROVIDER_3
</object>
<option value="<SAP_BW_URL ITEM='DDB_ITEM_1' HIDDEN='' IOBJNM='PRODUCT' CMD_1="DATA_PROVIDER=DATAPROVIDER_2& CMD=RESET_DATA_PROVIDER&DATA_PROVIDER=DATAPROVIDER_3"> "> product</option>
Finally I still have my old question with the nested dropdwonbox in WAD...can somebody tell me, if its possible to create this.
Message was edited by: Jens Harder