bug.js

var div = document.createElement('div')
div.innerHTML = "<script></script>"
var s = div.children[0]
s.src = "//connect.facebook.net/en_US/all.js#xfbml=1"

// true
s instanceof HTMLScriptElement

// Will NOT load the script
document.head.appendChild(s)

expected.js

var s = document.createElement('script')
s.src = "//connect.facebook.net/en_US/all.js#xfbml=1"

// true
s instanceof HTMLScriptElement

// Will load the script
document.head.appendChild(s)

Just tested. It's not because it's a sub-node, really just because it's created with innerHTML. I guess you can file that as a bug somewhere, but maybe there's an underlying explanation. Curious to know.

@david-treblig you are right I don't think it's a webkit bug either (tested on FF & safari too and I actually made that distinction when I submitted the bug over to chromium.)

I also think that the node is internally marked differently. I really think this is unintended behavior, but as my bug report are usually dismissed, I wouldn't be surprised if they dismiss it.

Thanks for the follow up David, I'm going to add your findings to the bug report https://code.google.com/p/chromium/issues/detail?id=448783&colspec=ID%20Pri%20M%20Week%20ReleaseBlock%20Cr%20Status%20Owner%20Summary%20OS%20Modified#makechanges

Dah, just found this http://www.w3.org/TR/2008/WD-html5-20080610/dom.html#innerhtml0

That's why.