HTML is parsed using golang.org/x/net/html which produces a tree.
The module provides basic functionality to compare HTML tags or nodes and their trees.
The search of an HTML tag using a *node.HTML type ignores pointers.
It always returns the first match. By ignoring some properties, tags like <button> are easy to count.
Text value of a tag (title, error message,...) can be checked.
Parsing is not done according to the complete syntax checker of HTML.
For instance, tags like <p> for which a closing tag would fail a comparison.
Siblings must always have the same order or comparison fails. Order of attributes is treated as irrelevant.
Detailed documentation includes examples.
v1.0.7 removes use of files in examples to run them on pkg.go.dev
v1.0.6 updates golang/go/x/net package to remove CVE-2022-27664 which does not affect x/net/html
v1.0.5 requires Go 1.16+ as ioutil package use is removed.
v1.0.4 requires Go 1.17+ which implements lazy loading of modules to avoid go.mod updates.
v1.0.0 was created on Go 1.12 which supports modules.