Why doesn't attr(attributeName, value) create a new Attr object in the DOM attributes NamedNodeMap?

Question

I can change the value attribute of a HTMLOptionElement by doing so:

sizeOptionToBeSelected.attr('value', '555');

It changes the value property of the HTMLOptionElement and the value in the DOM Attr object in the NamedNodeMap attributes property from the same HTMLOptionElement object.

But, I cannot create a new Attr "selected" or change the selected property of the HTMLOptionElement with the following code:

sizeOptionToBeSelected.attr('selected', 'true');

Why do you think this is? How can I do this?

From jquery documentation:

We can add an attribute the same way: $('#greatphoto').attr('title', 'Photo by Kelly Clark');

Additional explanations:
- The code runs inside the $(document).ready( function so there is no problem with the loading.
- I use the latest Google Chrome 8.0.552.215 beta.

Kind Regards,
Despot

Answer 1

jQuery, somewhat confusingly, tends to treat attributes and properties as the same thing. So $(elem).attr('selected', true) is actually setting elem's selected property to true, not its attribute.

There are very few reasons to need to set the selected attribute. Setting the selected (and defaultSelected) properties should suffice.

Also, bear in mind that the selected attribute corresponds to the default state, not the current state.