Is it valid to have multiple form input elements with the same name?

Question

Is it valid markup and is it valid to the html/http spec? If I wanted to have

<form>
<input name="email" />
<input name="email" />
<input name="email" />
</form>

is that valid?

Answer 1

As stated on SO:

The browsers are OK with it. However, how the application library parses it may vary.

Programs are supposed to group identically named items together. While the HTML specification doesn't explicitly say this, it is implicitly stated in the documentation on checkboxes:

"Several checkboxes in a form may share the same control name. Thus, for example, checkboxes allow users to select several values for the same property."

On a side note, in PHP you can have form fields with the same name if you use PHP's arry syntax for the field name:

<form>
<input name="email[]" />
<input name="email[]" />
<input name="email[]" />
</form>

This will cause the browser to send over the form fields in a syntax that PHP will use to populate an array for these fields: $_REQUEST['email']. If you use PHP this is the preferred way to handle it.