![\"json](\"https://www.json.org/img/json160.gif\")
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"nodeLabel": "json logo"
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]
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},
"deprecations": {
"id": "deprecations",
"title": "Avoids deprecated APIs",
"description": "Deprecated APIs will eventually be removed from the browser. [Learn more about deprecated APIs](https://developer.chrome.com/docs/lighthouse/best-practices/deprecations/).",
"score": 1,
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"details": {
"type": "table",
"headings": [
{
"key": "value",
"valueType": "text",
"label": "Deprecation / Warning"
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{
"key": "source",
"valueType": "source-location",
"label": "Source"
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},
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"id": "third-party-cookies",
"title": "Avoids third-party cookies",
"description": "Third-party cookies may be blocked in some contexts. [Learn more about preparing for third-party cookie restrictions](https://privacysandbox.google.com/cookies/prepare/overview).",
"score": 1,
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{
"key": "name",
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{
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"label": "URL"
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},
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"id": "mainthread-work-breakdown",
"title": "Minimizes main-thread work",
"description": "Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. [Learn how to minimize main-thread work](https://developer.chrome.com/docs/lighthouse/performance/mainthread-work-breakdown/)",
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{
"key": "groupLabel",
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"label": "Category"
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{
"key": "duration",
"valueType": "ms",
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"label": "Time Spent"
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],
"items": [
{
"group": "other",
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{
"group": "styleLayout",
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{
"group": "paintCompositeRender",
"groupLabel": "Rendering",
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{
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{
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{
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},
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"bootup-time": {
"id": "bootup-time",
"title": "JavaScript execution time",
"description": "Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this. [Learn how to reduce Javascript execution time](https://developer.chrome.com/docs/lighthouse/performance/bootup-time/).",
"score": 1,
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{
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"label": "URL"
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{
"key": "total",
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"label": "Total CPU Time"
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{
"key": "scripting",
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"label": "Script Evaluation"
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{
"key": "scriptParseCompile",
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"label": "Script Parse"
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{
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"title": "Network Requests",
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"details": {
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"headings": [
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"label": "URL"
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{
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"label": "Protocol"
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"label": "Network Request Time"
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"label": "Network End Time"
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"label": "Transfer Size"
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"label": "Resource Size"
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{
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"label": "Status Code"
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{
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"label": "MIME Type"
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{
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"priority": "High",
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"entity": "json.org"
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{
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{
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{
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"url": "https://www.json.org/json-en.html",
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{
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{
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{
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},
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"id": "network-rtt",
"title": "Network Round Trip Times",
"description": "Network round trip times (RTT) have a large impact on performance. If the RTT to an origin is high, it's an indication that servers closer to the user could improve performance. [Learn more about the Round Trip Time](https://hpbn.co/primer-on-latency-and-bandwidth/).",
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{
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"label": "Time Spent"
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"network-server-latency": {
"id": "network-server-latency",
"title": "Server Backend Latencies",
"description": "Server latencies can impact web performance. If the server latency of an origin is high, it's an indication the server is overloaded or has poor backend performance. [Learn more about server response time](https://hpbn.co/primer-on-web-performance/#analyzing-the-resource-waterfall).",
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"label": "Time Spent"
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{
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"label": "Start Time"
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"label": "End Time"
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},
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"label": "Requests"
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{
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"label": "Transfer Size"
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"items": [
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{
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{
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{
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{
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}
},
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"label": "Layout shift score"
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"cause": "Web font loaded"
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}
},
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}
},
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},
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"lhId": "page-8-CENTER",
"path": "1,HTML,1,BODY,6,DIV,0,DIV,14,CENTER",
"selector": "body > div#spec > div#text > center",
"boundingRect": {
"top": 2500,
"bottom": 3126,
"left": 57,
"right": 612,
"width": 555,
"height": 626
},
"snippet": "
![](\"https://www.json.org/img/string.png\")
",
"nodeLabel": "div#spec > div#text > center > img"
},
"cause": "Media element lacking an explicit size"
}
]
}
},
{
"node": {
"type": "node",
"lhId": "page-6-CENTER",
"path": "1,HTML,1,BODY,6,DIV,0,DIV,12,CENTER",
"selector": "body > div#spec > div#text > center",
"boundingRect": {
"top": 1768,
"bottom": 2432,
"left": 57,
"right": 612,
"width": 555,
"height": 664
},
"snippet": "![](\"https://www.json.org/img/array.png\")
",
"nodeLabel": "div#spec > div#text > center > img"
},
"cause": "Media element lacking an explicit size"
}
]
}
},
{
"node": {
"type": "node",
"lhId": "page-5-P",
"path": "1,HTML,1,BODY,6,DIV,0,DIV,15,P",
"selector": "body > div#spec > div#text > p",
"boundingRect": {
"top": 3142,
"bottom": 3178,
"left": 57,
"right": 612,
"width": 555,
"height": 36
},
"snippet": "",
"nodeLabel": "Whitespace can be inserted between any pair of tokens. Excepting a few encoding…"
},
"score": 0.004219,
"subItems": {
"type": "subitems",
"items": [
{
"extra": {
"type": "node",
"lhId": "page-0-IMG",
"path": "1,HTML,1,BODY,6,DIV,0,DIV,14,CENTER,0,IMG",
"selector": "div#spec > div#text > center > img",
"boundingRect": {
"top": 2500,
"bottom": 3121,
"left": 57,
"right": 612,
"width": 555,
"height": 621
},
"snippet": "![](\"https://www.json.org/img/number.png\")
",
"nodeLabel": "div#spec > div#text > center > img"
},
"cause": "Media element lacking an explicit size"
}
]
}
}
]
},
"guidanceLevel": 2
},
"long-tasks": {
"id": "long-tasks",
"title": "Avoid long main-thread tasks",
"description": "Lists the longest tasks on the main thread, useful for identifying worst contributors to input delay. [Learn how to avoid long main-thread tasks](https://web.dev/articles/optimize-long-tasks)",
"score": 1,
"scoreDisplayMode": "informative",
"displayValue": "1 long task found",
"metricSavings": {
"TBT": 0
},
"details": {
"type": "table",
"headings": [
{
"key": "url",
"valueType": "url",
"label": "URL"
},
{
"key": "startTime",
"valueType": "ms",
"granularity": 1,
"label": "Start Time"
},
{
"key": "duration",
"valueType": "ms",
"granularity": 1,
"label": "Duration"
}
],
"items": [
{
"url": "https://www.json.org/json-en.html",
"duration": 53,
"startTime": 1162.4586
}
],
"sortedBy": [
"duration"
],
"skipSumming": [
"startTime"
],
"debugData": {
"type": "debugdata",
"urls": [
"https://www.json.org/json-en.html"
],
"tasks": [
{
"urlIndex": 0,
"startTime": 1162.5,
"duration": 53,
"other": 53,
"paintCompositeRender": 0,
"scriptEvaluation": 0,
"styleLayout": 0
}
]
}
},
"guidanceLevel": 1
},
"non-composited-animations": {
"id": "non-composited-animations",
"title": "Avoid non-composited animations",
"description": "Animations which are not composited can be janky and increase CLS. [Learn how to avoid non-composited animations](https://developer.chrome.com/docs/lighthouse/performance/non-composited-animations/)",
"score": null,
"scoreDisplayMode": "notApplicable",
"metricSavings": {
"CLS": 0
},
"details": {
"type": "table",
"headings": [
{
"key": "node",
"valueType": "node",
"subItemsHeading": {
"key": "failureReason",
"valueType": "text"
},
"label": "Element"
}
],
"items": []
},
"guidanceLevel": 2
},
"unsized-images": {
"id": "unsized-images",
"title": "Image elements do not have explicit `width` and `height`",
"description": "Set an explicit width and height on image elements to reduce layout shifts and improve CLS. [Learn how to set image dimensions](https://web.dev/articles/optimize-cls#images_without_dimensions)",
"score": 0.5,
"scoreDisplayMode": "metricSavings",
"metricSavings": {
"CLS": 0
},
"details": {
"type": "table",
"headings": [
{
"key": "node",
"valueType": "node",
"label": ""
},
{
"key": "url",
"valueType": "url",
"label": "URL"
}
],
"items": [
{
"url": "https://www.json.org/img/string.png",
"node": {
"type": "node",
"lhId": "1-4-IMG",
"path": "1,HTML,1,BODY,6,DIV,0,DIV,12,CENTER,0,IMG",
"selector": "div#spec > div#text > center > img",
"boundingRect": {
"top": 1768,
"bottom": 2427,
"left": 57,
"right": 612,
"width": 555,
"height": 659
},
"snippet": "",
"nodeLabel": "div#spec > div#text > center > img"
}
},
{
"url": "https://www.json.org/img/number.png",
"node": {
"type": "node",
"lhId": "1-5-IMG",
"path": "1,HTML,1,BODY,6,DIV,0,DIV,14,CENTER,0,IMG",
"selector": "div#spec > div#text > center > img",
"boundingRect": {
"top": 2500,
"bottom": 3121,
"left": 57,
"right": 612,
"width": 555,
"height": 621
},
"snippet": "",
"nodeLabel": "div#spec > div#text > center > img"
}
},
{
"url": "https://www.json.org/img/value.png",
"node": {
"type": "node",
"lhId": "1-3-IMG",
"path": "1,HTML,1,BODY,6,DIV,0,DIV,10,CENTER,0,IMG",
"selector": "div#spec > div#text > center > img",
"boundingRect": {
"top": 1286,
"bottom": 1677,
"left": 57,
"right": 612,
"width": 555,
"height": 391
},
"snippet": "",
"nodeLabel": "div#spec > div#text > center > img"
}
},
{
"url": "https://www.json.org/img/whitespace.png",
"node": {
"type": "node",
"lhId": "1-6-IMG",
"path": "1,HTML,1,BODY,6,DIV,0,DIV,16,CENTER,0,IMG",
"selector": "div#spec > div#text > center > img",
"boundingRect": {
"top": 3194,
"bottom": 3482,
"left": 57,
"right": 612,
"width": 555,
"height": 288
},
"snippet": "![](\"https://www.json.org/img/whitespace.png\")
",
"nodeLabel": "div#spec > div#text > center > img"
}
},
{
"url": "https://www.json.org/img/object.png",
"node": {
"type": "node",
"lhId": "1-1-IMG",
"path": "1,HTML,1,BODY,6,DIV,0,DIV,6,CENTER,0,IMG",
"selector": "div#spec > div#text > center > img",
"boundingRect": {
"top": 736,
"bottom": 995,
"left": 57,
"right": 612,
"width": 555,
"height": 259
},
"snippet": "",
"nodeLabel": "div#spec > div#text > center > img"
}
},
{
"url": "https://www.json.org/img/array.png",
"node": {
"type": "node",
"lhId": "1-2-IMG",
"path": "1,HTML,1,BODY,6,DIV,0,DIV,8,CENTER,0,IMG",
"selector": "div#spec > div#text > center > img",
"boundingRect": {
"top": 1068,
"bottom": 1213,
"left": 57,
"right": 612,
"width": 555,
"height": 145
},
"snippet": "",
"nodeLabel": "div#spec > div#text > center > img"
}
}
]
},
"guidanceLevel": 4
},
"valid-source-maps": {
"id": "valid-source-maps",
"title": "Page has valid source maps",
"description": "Source maps translate minified code to the original source code. This helps developers debug in production. In addition, Lighthouse is able to provide further insights. Consider deploying source maps to take advantage of these benefits. [Learn more about source maps](https://developer.chrome.com/docs/devtools/javascript/source-maps/).",
"score": 1,
"scoreDisplayMode": "binary",
"details": {
"type": "table",
"headings": [
{
"key": "scriptUrl",
"valueType": "url",
"subItemsHeading": {
"key": "error"
},
"label": "URL"
},
{
"key": "sourceMapUrl",
"valueType": "url",
"label": "Map URL"
}
],
"items": []
}
},
"csp-xss": {
"id": "csp-xss",
"title": "Ensure CSP is effective against XSS attacks",
"description": "A strong Content Security Policy (CSP) significantly reduces the risk of cross-site scripting (XSS) attacks. [Learn how to use a CSP to prevent XSS](https://developer.chrome.com/docs/lighthouse/best-practices/csp-xss/)",
"score": 1,
"scoreDisplayMode": "informative",
"details": {
"type": "table",
"headings": [
{
"key": "description",
"valueType": "text",
"subItemsHeading": {
"key": "description"
},
"label": "Description"
},
{
"key": "directive",
"valueType": "code",
"subItemsHeading": {
"key": "directive"
},
"label": "Directive"
},
{
"key": "severity",
"valueType": "text",
"subItemsHeading": {
"key": "severity"
},
"label": "Severity"
}
],
"items": [
{
"severity": "High",
"description": "No CSP found in enforcement mode"
}
]
}
},
"has-hsts": {
"id": "has-hsts",
"title": "Use a strong HSTS policy",
"description": "Deployment of the HSTS header significantly reduces the risk of downgrading HTTP connections and eavesdropping attacks. A rollout in stages, starting with a low max-age is recommended. [Learn more about using a strong HSTS policy.](https://developer.chrome.com/docs/lighthouse/best-practices/has-hsts)",
"score": 1,
"scoreDisplayMode": "informative",
"details": {
"type": "table",
"headings": [
{
"key": "description",
"valueType": "text",
"subItemsHeading": {
"key": "description"
},
"label": "Description"
},
{
"key": "directive",
"valueType": "code",
"subItemsHeading": {
"key": "directive"
},
"label": "Directive"
},
{
"key": "severity",
"valueType": "text",
"subItemsHeading": {
"key": "severity"
},
"label": "Severity"
}
],
"items": [
{
"severity": "High",
"description": "No HSTS header found"
}
]
}
},
"origin-isolation": {
"id": "origin-isolation",
"title": "Ensure proper origin isolation with COOP",
"description": "The Cross-Origin-Opener-Policy (COOP) can be used to isolate the top-level window from other documents such as pop-ups. [Learn more about deploying the COOP header.](https://web.dev/articles/why-coop-coep#coop)",
"score": 1,
"scoreDisplayMode": "informative",
"details": {
"type": "table",
"headings": [
{
"key": "description",
"valueType": "text",
"subItemsHeading": {
"key": "description"
},
"label": "Description"
},
{
"key": "directive",
"valueType": "code",
"subItemsHeading": {
"key": "directive"
},
"label": "Directive"
},
{
"key": "severity",
"valueType": "text",
"subItemsHeading": {
"key": "severity"
},
"label": "Severity"
}
],
"items": [
{
"description": "No COOP header found",
"severity": "High"
}
]
}
},
"clickjacking-mitigation": {
"id": "clickjacking-mitigation",
"title": "Mitigate clickjacking with XFO or CSP",
"description": "The `X-Frame-Options` (XFO) header or the `frame-ancestors` directive in the `Content-Security-Policy` (CSP) header control where a page can be embedded. These can mitigate clickjacking attacks by blocking some or all sites from embedding the page. [Learn more about mitigating clickjacking](https://developer.chrome.com/docs/lighthouse/best-practices/clickjacking-mitigation).",
"score": 1,
"scoreDisplayMode": "informative",
"details": {
"type": "table",
"headings": [
{
"key": "description",
"valueType": "text",
"subItemsHeading": {
"key": "description"
},
"label": "Description"
},
{
"key": "severity",
"valueType": "text",
"subItemsHeading": {
"key": "severity"
},
"label": "Severity"
}
],
"items": [
{
"severity": "High",
"description": "No frame control policy found"
}
]
}
},
"trusted-types-xss": {
"id": "trusted-types-xss",
"title": "Mitigate DOM-based XSS with Trusted Types",
"description": "The `require-trusted-types-for` directive in the `Content-Security-Policy` (CSP) header instructs user agents to control the data passed to DOM XSS sink functions. [Learn more about mitigating DOM-based XSS with Trusted Types](https://developer.chrome.com/docs/lighthouse/best-practices/trusted-types-xss).",
"score": 1,
"scoreDisplayMode": "informative",
"details": {
"type": "table",
"headings": [
{
"key": "description",
"valueType": "text",
"subItemsHeading": {
"key": "description"
},
"label": "Description"
},
{
"key": "severity",
"valueType": "text",
"subItemsHeading": {
"key": "severity"
},
"label": "Severity"
}
],
"items": [
{
"severity": "High",
"description": "No `Content-Security-Policy` header with Trusted Types directive found"
}
]
}
},
"script-treemap-data": {
"id": "script-treemap-data",
"title": "Script Treemap Data",
"description": "Used for treemap app",
"score": 1,
"scoreDisplayMode": "informative",
"details": {
"type": "treemap-data",
"nodes": []
}
},
"accesskeys": {
"id": "accesskeys",
"title": "`[accesskey]` values are unique",
"description": "Access keys let users quickly focus a part of the page. For proper navigation, each access key must be unique. [Learn more about access keys](https://dequeuniversity.com/rules/axe/4.11/accesskeys).",
"score": null,
"scoreDisplayMode": "notApplicable"
},
"aria-allowed-attr": {
"id": "aria-allowed-attr",
"title": "`[aria-*]` attributes match their roles",
"description": "Each ARIA `role` supports a specific subset of `aria-*` attributes. Mismatching these invalidates the `aria-*` attributes. [Learn how to match ARIA attributes to their roles](https://dequeuniversity.com/rules/axe/4.11/aria-allowed-attr).",
"score": null,
"scoreDisplayMode": "notApplicable"
},
"aria-allowed-role": {
"id": "aria-allowed-role",
"title": "Uses ARIA roles only on compatible elements",
"description": "Many HTML elements can only be assigned certain ARIA roles. Using ARIA roles where they are not allowed can interfere with the accessibility of the web page. [Learn more about ARIA roles](https://dequeuniversity.com/rules/axe/4.11/aria-allowed-role).",
"score": null,
"scoreDisplayMode": "notApplicable"
},
"aria-command-name": {
"id": "aria-command-name",
"title": "`button`, `link`, and `menuitem` elements have accessible names",
"description": "When an element doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. [Learn how to make command elements more accessible](https://dequeuniversity.com/rules/axe/4.11/aria-command-name).",
"score": null,
"scoreDisplayMode": "notApplicable"
},
"aria-conditional-attr": {
"id": "aria-conditional-attr",
"title": "ARIA attributes are used as specified for the element's role",
"description": "Some ARIA attributes are only allowed on an element under certain conditions. [Learn more about conditional ARIA attributes](https://dequeuniversity.com/rules/axe/4.11/aria-conditional-attr).",
"score": null,
"scoreDisplayMode": "notApplicable"
},
"aria-deprecated-role": {
"id": "aria-deprecated-role",
"title": "Deprecated ARIA roles were not used",
"description": "Deprecated ARIA roles may not be processed correctly by assistive technology. [Learn more about deprecated ARIA roles](https://dequeuniversity.com/rules/axe/4.11/aria-deprecated-role).",
"score": null,
"scoreDisplayMode": "notApplicable"
},
"aria-dialog-name": {
"id": "aria-dialog-name",
"title": "Elements with `role=\"dialog\"` or `role=\"alertdialog\"` have accessible names.",
"description": "ARIA dialog elements without accessible names may prevent screen readers users from discerning the purpose of these elements. [Learn how to make ARIA dialog elements more accessible](https://dequeuniversity.com/rules/axe/4.11/aria-dialog-name).",
"score": null,
"scoreDisplayMode": "notApplicable"
},
"aria-hidden-body": {
"id": "aria-hidden-body",
"title": "`[aria-hidden=\"true\"]` is not present on the document `
- `'s contain only properly-ordered `
- ` and `
- ` groups, `