In order to add the Page-Level ads functionality from AdSense on your Blogger blog you are required to place a code that AdSense provides which is :
Unfortunately if you have tried placing the code in your theme you may have run into this error that states:
<script async src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"/>
Unfortunately if you have tried placing the code in your theme you may have run into this error that states:
Error parsing XML, line n, column n: Attribute name "async" associated with an element type "script" must be followed by the ' = ' character.
That's a bit annoying - What could be going wrong with the code that AdSense (a Google product) has provided is causing error on Blogger (another Google product).
The problem is highlighted in the error message itself "Attribute name "async" associated with an element type "script" must be followed by the ' = ' character."
Attribute name "async" in the code we got must be followed by a '=' character. But the code we got simply has
<script async ... />
So what can be done? Modify the code to be parsed by Blogger's theme parser correctly. Here's the code with a little change, we replaced async with async="async" to make the code a valid XHTML markup.
<script async="async" src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>
Place this code in your Blogger theme code and save. It should work properly now.
Why do we have to use this "hack"?
This shouldn't even be considered as a hack. This is plainly a case where a valud HTML5 markup is not parsed as a valid XML / XHTML markup.
Yes, our blogs are HTML5 in the end when it gets loaded on a web browser, but the code that runs in the background is XHTML, and the thing with XHTML is that it is very strict about the markup language. In HTML5 you can simply leave out a value from a attribute or leave an HTML element unclosed and it will still work.
But XHTML won't. What's valid in XHTML is also valid in HTML5, so this don't need to be considered a hack or even a workaround. AdSense provides the code that is totally HTML5 compliant only it didn't anticipate the case where users may want to add the code to XHTML templates.
Will it have any impact on the way this code is supposed to work?
Other than having a few extra characters in the code you had to add, no. This change wouldn't affect anything how AdSense is supposed to work. We just made the code compliant with XHTML to be taken in by Blogger.