How to fix w3.org validation error: There is no attribute “sid” or, Element “iframe” undefined?

Question

i am trying to validate someone else's code here and they are using the xhtml1-strict DOCTYPE.

i am almost there; except for few erors...

• There is no attribute "sid"
• Element "iframe" undefined

For the SID attribute issue, this is what they have:

    <li class="drop" sid="nav_products"> <span class="head">Our Products</span>
    <ul id="nav_products" style="display: none;">

      <li><a href="/products/itemNumOne.php">Toys</a></li>

      <li><a href="/products/itemNumTwo.php">Tools</a></li>

      <li><a href="/products/itemNumThree.php">Beauty</a></li>

      <li><a href="/products/itemNumFour.php">Electronics</a></li>

    </ul>
    </li>

And because of the IFRAME error, i am also getting 2 more errors:

• there is no attribute "src"

• there is no attribute "style"

  <h2>Read The Latest News</h2>
  <iframe src="http://p.p0.com/YesConnect/HtmlMessagePreview?a=TiTnp" style="width:100%; height:4350px; border-collapse:collapse; border:1px solid #ccc; padding:10px 0 0"></iframe>
  

Can anyone PLEASE help me fix these errors? I am not an expert in this area, so you will have to explain a bit the solutions. Thanks a lot in advance for your time and help!!!

Answer 1

The question to ask is probably why the previous developer was using "sid" in the first place. As far as I know, attribute "sid" will never validate in any XHTML doctype, so it's a good idea to change it to "class" or "id", and then change the code that relies on "sid" accordingly.

Answer 2

Okay, so I was googling for solutions and found this site that kind of answered my questions on iframe

• http://madskristensen.net/post/Use-iframes-with-XHTML-10-Strict.aspx

So I ended up changing the DOCTYPE for that one page to "XHTML 1.0 Transitional" from "XHTML 1.0 Strict" and that fixed all 3 errors I was getting for using iframe. Hope this info helps someone :)

however, i am still stuck with the error for sid, any help will be greatly appreciated!

UPDATE: This answer is almost 6 yrs old, and looks like since then few things have changed :P As Davide Andrea had pointed out, the above link doesn't work anymore, some of you might find this answer helpful: https://stackoverflow.com/a/8265544/1081016