Table of contents (SEO)
An HTML table of contents with named anchors improves navigation on long content and can trigger jump link display in Google results, increasing visibility and CTR without any change in ranking position. The effect is most pronounced on mobile SERPs.
In practice
The table of contents must use href links pointing to id anchors placed on the corresponding H2 and H3 headings. Google can then display up to three 'jump to' links below the result on mobile. This mechanism is particularly effective on long guides (over 1,500 words): a legal directory increased its CTR by 22% after adding tables of contents to its 80 guides.