& as an escape character only applies to text nodes. Of course, if you want to display the URL on a page, you have to escape it, but not in the href.

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_micheee 2 days ago | parent | next [-]

I just found out you may - even in current HTML use entity references in attribute values, it’s just you don’t have to anymore, when the ampersand is not ambiguous.

The spec states it as: “Attribute values are a mixture of text and character references, except with the additional restriction that the text cannot contain an ambiguous ampersand.”

Whereas in the the days before HTML5 this has been mandatory.

> HTML 4.01 Specification – Appendix B.2.2 “Ampersands in URI attribute values”

https://www.w3.org/TR/html401/appendix/notes.html#h-B.2.2

> Unfortunately, the use of the “&” character to separate form fields interacts with its use in SGML attribute values to delimit character entity references.

	▲	someonebaggy 2 days ago \| parent [-]
		That's the same as main body text isn't it? And you have to be able to use them so you can escape " just like you have to escape < in main text. HTML5 standardized how to interpret formerly invalid documents because it was more important to be consistent than to be correct.

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ShinyLeftPad 2 days ago | parent | prev | next [-]

You're supposed to escape & anywhere in HTML, not just in text nodes. If you don't (and many don't) it'll probably work, but browser first tries to interpret it as a start of an entity anyway. Even if it is inside a href etc.

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bawolff 2 days ago | parent | prev [-]

That is incorrect. Entities apply to attributes.

In HTML escaping & is kind of optional and the browser just tries to figure out what you mean, but if you are doing things properly you should use & in href attributes.