- Response Codes
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Internal No Response
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Internal Client Error (4XX)
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Internal Server Error (5XX)
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Internal Redirect Loop
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Internal Blocked by Robots.txt
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Internal Blocked Resource
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Internal Redirect Chain
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External Blocked Resource
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Internal Redirection (3XX)
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Internal Redirection (Meta Refresh)
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Internal Redirection (JavaScript)
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External No Response
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External Client Error (4XX)
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External Server Error (5XX)
- Security
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HTTP URLs
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Mixed Content
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Form URL Insecure
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Form On HTTP URL
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Missing HSTS Header
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Unsafe Cross Origin Links
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Protocol-Relative Resource Links
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Missing Content-Security-Policy Header
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Missing X-Content-Type-Options Header
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Missing X-Frames-Options Header
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Missing Secure Referrer-Policy Header
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Bad Content Type
- Hreflang
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Non-200 Hreflang URLs
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Missing Return Links
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Inconsistent Language & Region Confirmation Links
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Non-Canonical Return Links
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Noindex Returns Links
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Incorrect Language & Region Codes
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Multiple Entries
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Not Using Canonical
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Outside <head>
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Unlinked Hreflang URLs
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Missing Self Reference
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Missing X-Default
- JavaScript
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Noindex Only in Original HTML
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Nofollow Only in Original HTML
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Canonical Mismatch
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Uses Old AJAX Crawling Scheme URLs
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Uses Old AJAX Crawling Scheme Meta Fragment Tag
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Pages with Blocked Resources
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Contains JavaScript Links
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Contains JavaScript Content
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Page Title Only in Rendered HTML
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Page Title Updated by JavaScript
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Meta Description Only in Rendered HTML
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Meta Description Updated by JavaScript
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H1 Only in Rendered HTML
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H1 Updated by JavaScript
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Canonical Only in Rendered HTML
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Pages With JavaScript Errors
- Links
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Outlinks To Localhost
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Pages Without Internal Outlinks
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Non-Indexable Page Inlinks Only
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Internal Nofollow Outlinks
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Pages With High External Outlinks
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Pages With High Internal Outlinks
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Follow & Nofollow Internal Inlinks To Page
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Internal Nofollow Inlinks Only
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Pages With High Crawl Depth
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Internal Outlinks With No Anchor Text
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Non-Descriptive Anchor Text In Internal Outlinks
- AMP
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Non-200 Response
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Missing Non-AMP Return Link
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Missing Canonical to Non-AMP
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Non-Indexable Canonical
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Missing <html amp> Tag
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Missing/Invalid Doctype HTML Tag
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Missing Head Tag
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Missing Body Tag
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Missing Canonical
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Missing/Invalid Meta Charset Tag
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Missing/Invalid Meta Viewport Tag
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Missing/Invalid AMP Script
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Missing/Invalid AMP Boilerplate
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Contains Disallowed HTML
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Other Validation Errors
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Indexable
- PageSpeed
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Eliminate Render-Blocking Resources
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Properly Size Images
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Defer Offscreen Images
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Minify CSS
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Minify JavaScript
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Reduce Unused CSS
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Reduce Unused JavaScript
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Efficiently Encode Images
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Serve Images in Next-Gen Formats
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Enable Text Compression
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Preconnect to Required Origin
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Reduce Server Response Times (TTFB)
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Preload Key Requests
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Reduce JavaScript Execution Time
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Serve Static Assets With An Efficient Cache Policy
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Minimize Main-Thread Work
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Image Elements Do Not Have Explicit Width & Height
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Avoid Large Layout Shifts
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Avoid Serving Legacy JavaScript to Modern Browsers
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Avoid Multiple Page Redirects
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Use Video Format for Animated Images
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Avoid Excessive DOM Size
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Ensure Text Remains Visible During Webfont Load
- Accessibility
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Best Practice – Accesskey Attribute Value Must Be Unique
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Best Practice – Elements Must Not Have Tabindex Greater Than Zero
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Best Practice – ARIA Dialog & Alertdialog Require Accessible Name
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Best Practice – ARIA Treeitem Nodes Require Accessible Name
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Best Practice – Role=text Should Have No Focusable Descendants
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Best Practice – Form Elements Should Have Visible Label
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Best Practice – Frames Should Be Tested With axe-core
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Best Practice – Scope Attribute Should Be Used Correctly On Tables
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WCAG 2.0 A – Scrollable Region Requires Keyboard Access
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WCAG 2.0 A – Required ARIA Attributes Must Be Provided
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WCAG 2.0 A – ARIA Attribute Must Be Used As Specified For Role
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WCAG 2.0 A – ARIA Attributes Require Valid Values
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WCAG 2.0 A – ARIA Attributes Require Valid Names
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WCAG 2.0 A – ARIA Commands Require Accessible Name
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WCAG 2.0 A – ARIA Input Fields Require Accessible Name
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WCAG 2.0 A – ARIA Meter Nodes Require Accessible Name
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WCAG 2.0 A – ARIA Progressbar Nodes Require Accessible Name
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WCAG 2.0 A – ARIA Roles Must Be Contained By Required Parent
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WCAG 2.0 A – ARIA Roles Require Valid Values
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WCAG 2.0 A – ARIA Toggle Fields Require Accessible Name
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WCAG 2.0 A – ARIA Tooltip Nodes Require Accessible Name
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WCAG 2.0 A – Certain ARIA Roles Must Contain Specific Children
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WCAG 2.0 A – Aria-braille Require Non-braille Equivalent
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WCAG 2.0 A – Aria-hidden Elements Contains Focusable Elements
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WCAG 2.0 A – Aria-hidden=true Must Not Be Used In <body>
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WCAG 2.0 A – Elements Must Only Use Permitted ARIA Attributes
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WCAG 2.0 A – Elements Must Use Allowed ARIA Attributes
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WCAG 2.0 A – IDs Used In ARIA & Labels Must Be Unique
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WCAG 2.0 A – Page Requires Means To Bypass Repeated Blocks
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WCAG 2.0 A – Form <input> Elements Require Labels
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WCAG 2.0 A – Frames Require Title Attribute
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WCAG 2.0 A – Frames Require Unique Title Attribute
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WCAG 2.0 A – Frames With Focusable Content Must Not Use tabindex=-1
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WCAG 2.0 A – Page Must Contain <title>
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WCAG 2.0 A – HTML Element Lang Attribute Value Must Be Valid
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WCAG 2.0 A – HTML Element Requires Lang Attribute
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WCAG 2.0 A – Image Button Requires Alternate Text
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WCAG 2.0 A – Images Require Alternate Text
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WCAG 2.0 A – <object> Elements Require Alternate Text
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WCAG 2.0 A – Active <area> Elements Require Alternate Text
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WCAG 2.0 A – Elements Marked role=img Require Alternate Text
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WCAG 2.0 A – SVG Images & Graphics Require Accessible Text
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WCAG 2.0 A – <video> Elements Require <track> For Captions
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WCAG 2.0 A – <video> or <audio> Elements Must Not Auto-play
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WCAG 2.0 A – Buttons Require Discernible Text
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WCAG 2.0 A – Input Buttons Require Discernible Text
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WCAG 2.0 A – Links Require Discernible Text
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WCAG 2.0 A – Links Must Be Distinguishable
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WCAG 2.0 A – Select Element Requires Accessible Name
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WCAG 2.0 A – Summary Elements Require Discernible Text
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WCAG 2.0 A – Deprecated <marquee> Element Must Not Be Used
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WCAG 2.0 A – Interactive Controls Must Not Be Nested
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WCAG 2.0 A – List Items Must Be Contained In List Elements
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WCAG 2.0 A – Lists Must Only Contain <li> Content Elements
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WCAG 2.0 A – <dt> & <dd> Elements Must Be Contained by <dl>
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WCAG 2.0 A – <dl> Must Only Have Ordered <dt> & <dd> Groups
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WCAG 2.0 A – <blink> Elements Deprecated & Must Not Be Used
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WCAG 2.0 A – <th> Element Requires Associated Data Cells
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WCAG 2.0 A – Table Header Attr Must Refer To Cell In Same Table
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WCAG 2.0 AA – Meta Viewport Zoom & Scaling Disabled
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WCAG 2.0 AA – Lang Attribute Requires Valid Value
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WCAG 2.0 AA – Text Requires Higher Color Contrast to Background
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WCAG 2.0 AAA – Text Requires Higher Color Contrast Ratio
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WCAG 2.1 AA – Autocomplete Attribute Must Be Used Correctly
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WCAG 2.1 AA – Inline Text Spacing Must Be Adjustable
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WCAG 2.2 AA – Touch Targets Require Sufficient Size & Spacing
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Best Practice – Skip-link Target Should Exist & Be Focusable
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Best Practice – All Page Content Must Be Contained By Landmarks
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Best Practice – Page Requires One Main Landmark
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Best Practice – Page Must Not Have More Than One Banner Landmark
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Best Practice – Banner Landmark Must Not Be In Another Landmark
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Best Practice – Page Must Not Have Multiple Contentinfo Landmarks
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Best Practice – Page Requires At Most One Main Landmark
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Best Practice – Complementary Landmarks & Asides Must Be Top Level
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Best Practice – Contentinfo Landmark Must Be Top Level Landmark
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Best Practice – Main Landmark Must Not Be In Another Landmark
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Best Practice – Landmarks Require Unique Role Or Accessible Name
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Best Practice – Page Must Contain <h1>
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Best Practice – Heading Levels Should Only Increase By One
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WCAG 2.0 A – Form Field Must Not Have Multiple Label Elements
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WCAG 2.0 A – HTML Lang & XML Lang Value Should Match
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Best Practice – Ensure Elements Marked Presentational Are Ignored
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Best Practice – ARIA Role Should Be Appropriate For Element
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Best Practice – Headings Should Not Be Empty
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Best Practice – Meta Viewport Should Allow Zoom & Scale Up to 500%
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Best Practice – Alt Text Should Not Be Repeated As Text
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Best Practice – Table Headers Require Discernible Text
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Best Practice – Table With Identical Summary & Caption Text
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WCAG 2.0 A – Deprecated ARIA Roles Must Not Be Used
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WCAG 2.0 A – Server-Side Image Maps Must Not Be Used
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WCAG 2.0 AAA – Delayed Meta Refresh Must Not Be Used
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WCAG 2.0 AAA – Links With Same Accessible Name
WCAG 2.0 A – HTML Element Requires Lang Attribute
The HTML document element must contain a valid lang attribute or must correspond to a valid lang code for multilingual screen reader users who may prefer a language other than the default.
How to Analyse in the SEO Spider
To populate this filter ‘Accessibility’ must be enabled via ‘Config > Spider > Extraction’ and ‘JavaScript rendering’ mode via ‘Config > Spider > Rendering’.
View URLs with this issue in the ‘Accessibility’ tab and ‘HTML Element Requires Lang Attribute’ filter.
Use the lower ‘Accessibility Details’ tab to click on the issue on the left-hand side, and see details of the location on the page of the violation on the right-hand side.
Bulk export the pages and details of the accessibility violations via ‘Bulk Export > Accessibility > All Violations’.
What Triggers This Issue
Please view the Deque University website further reading link below for ruleset triggers.
How To Fix
Ensure every HTML document has a lang attribute.
Further Reading
- HTML element must have a lang attribute - From Deque University