Fixing XHTML Parsing Error on Chrome: Specification mandate value for attribute async

This error message on Google Chrome console:

Specification mandate value for attribute async

That would happen if we generated XML page which acted as HTML, or XHTML. And we forgot to define the value for a particular HTML element attribute.

In this case, the value for async attribute (in script element).

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The "async" Attribute Strictly Needs Value in XHTML

Earlier, it was like this:

<script type="application/javascript" src="URL_SOURCE" async></script>

And the XHTML page wouldn't be rendered. It was just blank, but still with the XML attached (if we view the page source/inspect element).

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Solution

To fix that, put the value for that attribute. We can put async, 1, or true for that.

Use async:

<script type="application/javascript" src="URL_SOURCE" async="async"></script>

Or use 1:

<script type="application/javascript" src="URL_SOURCE" async="1"></script>

Or use true:

<script type="application/javascript" src="URL_SOURCE" async="true"></script>

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Other Browsers

It will have different error message. But that's the general method to fix it.