display of drop down menu form

[ketanco]

Hello,
In a drop down menu form:
1-After displaying the selections of the first question, how can you dispay the second questions' selections based on the first selection?(i.e. after user selects a car brand, the second choice display the models available of that brand)
2-After user submits his choice, I want the selection form and submit button to stay where it is and at the same time I want the results show up right under/near it. So when the user selects from the form again, the new results will be displayed, and the selection form will still stay and so on... How should the form submission work in that case? (i.e target frame self or something else and/or action = the file itself or another file is needed?

[sfullman]

your question on heirarchical displays is primarily a javascript issue - go to many car parts websites and you can see great examples of dropdown menus/options appearing based on the parent selection - either you can load all the heirarchy in a javascript array, or you can send a signal onchange() for the dropdown, to an iframe or by ajax. You are taking on one of the more advanced projects there is, so I suggest you write out a game plan on this and start with a single step. You can have the query string "set" all values in the tree if you wish to show the page already drilled-down, so

<select name="maincat">
<option value='1' <?php echo $maincat==1?'selected':''?>>option 1</option>
<option value='2' <?php echo $maincat==2?'selected':''?>>option 2</option>
<option value='3' <?php echo $maincat==3?'selected':''?>>option 3</option>
<option value='4' <?php echo $maincat==4?'selected':''?>>option 4</option>
.. etc.
</select>