auto update on form

redlamb

I have a form that I need updated when a user selects a particular option from a drop down box, but all the options are in a database.

For example: If I am trying to enter information on a car, an part on the car would be tires, but different tires are ade by different manufactures. So what i want is when the user selects "Goodyear" from a drop down box, I want the model drop down to display the list of tires from "Goodyear".

Now the form that im creating has about 5 different components that i would like to do this to where the user selects the different options and then submits the form. I want to reduce the number of pages that the user has to go through to enter all the info.

I am able to perform the query to get all the information from the database, but im unsure about the approach to take to setup this form that I want. Does anyone have any ideas on how to accomplish this or have a better approach to take? Thanks in advance and i hope that this makes sense..

sarahk

alot of how you work this will depend on your users

are they on dialup or fast connections
are they using up to date browsers, preferably sticking with IE or Netscape but not both

Now if you can't control the browser you will go for one of the "flickering" options as too much javascript leads to compatability problems.

So ... the choices

Submit the form every time a choice is made, annoying for the user if the form is complex but technically it's as safe as can be.
Use lots of iframes to query the database for the contents of the drop downs based upon current selects - see http://property.digitalrice.com/muck/example.html, it's slow but I think that's my connection and the host. We've used iframes on commercial projects with no problems. Once the iframe returns use javascript to feed back the results.
Build all the rules about the choices into arrays and javascript logic and manipulate them. High Risk but neat user experience

jowatkins

I did this using php one a project that I did for work.

pre-define all variables.

i.e.

if (!isset($manufacturer)
{
$manufacturer = "";
}

then do your dropdown from the query as normal, but pass in the existing value and add an on-click event:

echo "<select name=\"manufacturer\" value=\"$manufacturer\" onChange=\"document.manufacturerForm.submit();\">";

then just pass in the related item as part of a where clause on your follow up query.

so maybe:

SELECT model FROM table WHERE manufacturer='$manufacturer'

The only thing with this is each dropdown list that you want to auto-refresh has to be within it's own form tags, and that to pass that data on to a second page you need to place the values in hidden fields in a final "proceed" form.

sarahk

Thanks JoWatkins for the practical example of how to submit a form after the user has made a selection. This is the driver behind option 1. In Options 2 and 3 you would need to change the OnChange event to call your javascript functions.