HTML attributes with double quotes in them break parsing about php-html-parser

[paquettg]

I agree that we should handle this. I am more curious in knowing how you think we should handle this.

I have a few ideas but I am not fully aware of how browsers do this. If you have any insight into this or any ideas please let me know.

thanks

[dirtside]

Ultimately it comes down to detecting the > that ends the start tag, which can be tricky if there's multiple > inside other attributes in the tag, or an uneven number of " marks spread across one or more attributes. I assume browsers use some complicated heuristics, but messing around with various befunged attributes in Firefox, it looks like it treats the first > that's not inside an attribute (that is, not between a matching pair of " marks) as the end of the open tag. Everything after that (until a <) is considered part of the body of the element.

So there'd be two main (non-nominal) cases: an attribute with an extra pair of unescaped " inside of it (e.g. <a title="This "is" an attribute">), and an attribute with one extra " inside it (e.g. <a title="This "is an attribute">). The former is obviously easier; the latter could be treated as having one attribute called title with value This, and three other attributes named is, an, and attribute, each with empty values (the " immediately after attribute would be discarded as an invalid token since you can't have a double quote after an attribute name, there has to be an = first). The > is thus not inside an attribute, from the parser's POV, and ends the tag.

Another edge case is something like this: <span title=">something</span>. Firefox discards the entire thing as unparseable.

Presumably the corresponding logic can be found (somewhere) in the vast Firefox (Gecko?) and Chrome (Chromium) codebases.