Forcing the selection of an attribute

How and/or what do I need to do so that an item can not be added to the cart until either a drop down is selected and/or radio button selected?

Example:

Rim A:

Comes in red / silver / black / gold
Comes in 15"/16"/17"/18"

fastdc5:

How and/or what do I need to do so that an item can not be added to the cart until either a drop down is selected and/or radio button selected?

Example:

Rim A:

Comes in red / silver / black / gold
Comes in 15"/16"/17"/18"

Fa,
This will come in handy for you..

Attributes, Force to Select

Right now I can add to the cart and not select a color.. BAD. I am automatically linked to the shopping cart with the default color Black, but really I wanted White..

The beauty of this procedure: Is a warning box appears at the top of the page stating they have not selected a attribute color you offer to the customer.

Example of what it should look like in the Option Value Manager:

1. Add the following Option Values below
2. color Please Select Color: 0
3. Now that we added this it should look like this below

Please Select Color 0
Red 10
Silver 20
Black 30
Gold 40

Now in Attribute Controller for the product with this Option Name Value:

1. Add, Please Select Color to product, sort order 0
2. Associate the flag properties to Please Select Color
3. Under Attribute Flags: the colored boxes
4. Yellow box, Used for Display purpose only: Click Yes
5. Tan box, Default Attribute to be marked selected: Click Yes
6. Now when you click the add to cart a warning flag will appear for the customer to choose a size.

https://www.zen-cart.com/tutorials/index.php?article=190