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オンページSEOアナライザー・HTML構造診断
オンページSEOアナライザー・HTML構造診断
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コアアーキテクチャ & 計算式
Topical Relevance = Keyword Proximity (Title) + Semantic Structure (H1 to H6) + Context (Meta Description)
Search engines construct a document outline based on heading tags. Skipping from an H1 directly to an H4 breaks this outline and degrades the page's accessibility score.
ベストプラクティスとガイドライン
- Enforce the Single H1 Rule: While HTML5 technically permits multiple H1 tags per page, best practice dictates using exactly one H1 to clearly signal the primary topic of the document to search engine crawlers.
- Optimize Image Alt Text: Search engines cannot visually 'see' images. Always include descriptive `alt` attributes on `<img>` tags to provide context for screen readers and Google Image search indexing.
- Prevent Keyword Cannibalization: Ensure that every page on your domain targets a unique primary keyword in its Title tag. If five pages all use the same title, Google will struggle to determine which one to rank.
よくある質問 (FAQ)
Do Meta Descriptions affect Google rankings?
Not directly. Google has stated that meta descriptions are not a direct ranking factor. However, a well written description drastically improves the Click Through Rate (CTR) from the search results, which is a powerful indirect ranking signal.
How long should a Title tag be?
Search engines typically display the first 50 to 60 characters of a title tag. If your title exceeds 600 pixels in width, Google will truncate it with an ellipsis in the search results.
Does HTML validation matter for SEO?
Minor HTML validation errors (like unclosed tags) generally do not hurt SEO, as modern browsers are highly forgiving. However, severe structural errors that prevent Googlebot from rendering the DOM will destroy your rankings.