Saturday, November 11th, 2006

document.write and xhtml

Category: Tip

Sam Ruby knew that document.write doesn’t work well with XHTML so he went to find the best solution.

His context:

Because Google AdSense depends on document.write, the net result is that I only serve ads to users of browsers that don’t support XHTML, which increasingly means that only IE users see ads.

His solution:

The solution is to use createElementNS instead. So far, so good. The only piece left to the puzzle is where to append the child that you created. If you simply do a document.appendChild, the new element ends up at the end of the document. There doesn’t seem to be a property which indicates the current node in the tree at the time of the parse. But in cases like adsense, you generally want the widget put in place.

The code:


  1. var pos = document;
  2. while (pos.lastChild.nodeType == 1) pos = pos.lastChild;
  3. pos.parentNode.appendChild(...);

Could document.write be redefined if in an xhtml document to parse into a tree and append?

Posted by Dion Almaer at 7:37 am

4.1 rating from 28 votes


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Comment by Leonardo Priori — November 11, 2006

Only in the case where both the enclosing document and string are separately well formed. As Ian points out, that’s not necessarily always the case, but not supporting document.write at all simply because you might start a tag outside the script and close it inside the script is like saying that you won’t support division because the denominator might be zero.

Comment by Sam Ruby — November 11, 2006

What about just doing this (or something similiar)?

document.write = function(e){
var span = document.createElement(‘SPAN’);
span.innerHTML = e;

Comment by Mark Kahn — November 11, 2006

In XHTML, there is no document.body

Comment by Dominic Mitchell — November 11, 2006

Hawt! Gotta remember this one.

Comment by Ryan Brooks — November 11, 2006

@ Mark,

this is what I tried out yesterday, too ;) But it doesn’t work as well as “native” document write. If you include a js file, the content is not executed. E.g. an alert(1) is made in native mode, but not in all browsers for overwritten version of document.write. I will work meticulously.


Comment by Andreas Kalsch — November 12, 2006

I talk about including a JS script by document.write, e.g.


Comment by Andreas Kalsch — November 12, 2006

XHTML, document.write, and Adsense

After some recent discussion concerning the use of document.write() in XHTML documents served with the doctype “application/xhtml+xml” I decided to revisit the problem. An issue with the solutions proposed by Sam and Ajaxian is that they aren’t real…

Trackback by John Resig — November 12, 2006

document.write and xhtml

what if we give the script tag an id and drill it down from the document then append?
I will use JSON for this so that it is universal to all browsers and doc types.
For example:
var AdSense;
//this one return an object that has a method that does the…

Trackback by Programming in the State of 70% Drunkeness — November 13, 2006

there is no document.body in xhtml?

Comment by Ross Johnson — September 11, 2007

document.write() support for XHTML:

Comment by westonruter — May 28, 2008

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