I need to know if a tag is async by parsing html. I got a problem that I can't find any document about the valid value (and meaning) of async attribute.
What I know is that for async the valid value is:
for non-async:
what does async="" mean? and any other value?
According to the specification it is:
async = "async" or "" (empty string) or empty
(where empty means async, without assigning a value)
Its meaning:
Specifies that the script should be executed asynchronously, as soon as it becomes available.
So the browser should attempt to download the script file, without waiting to continue parsing the page. It loads the script as soon as it is done downloading.
