For a given set of browsers what APIs are still considred experimental, and how long have they been experimental?
Below is a list of features that are marked as "Experimental" in Safari and Safari on iOS
| API | First Browser | Date | Last Browser | Date | Days in experimentation | Notes |
|---|---|---|---|---|---|---|
| html.elements.a.attributionsourceid 📋 | Safari | 4/26/2021 | Safari on iOS | 4/26/2021 | 0 | |
| html.elements.input.alpha 📋 | Safari | 3/31/2025 | Safari on iOS | 3/31/2025 | 0 | |
| html.elements.input.colorspace 📋 | Safari | 3/31/2025 | Safari on iOS | 3/31/2025 | 0 | |
| html.elements.input.switch | Safari | 3/5/2024 | Safari on iOS | 3/5/2024 | 0 | |
| html.elements.script.type.speculationrules 📋 | Safari | 12/12/2025 | Safari on iOS | 12/12/2025 | 0 | Chrome: Initial support included same-origin prerendering only.Chrome Android: Initial support included same-origin prerendering only.Edge: Initial support included same-origin prerendering only.Quest Browser: Initial support included same-origin prerendering only.Opera: Initial support included same-origin prerendering only.Opera Android: Initial support included same-origin prerendering only.Samsung Internet: Initial support included same-origin prerendering only.WebView Android: Initial support included same-origin prerendering only. |
| html.elements.script.type.speculationrules.eagerness 📋 | Safari | 12/12/2025 | Safari on iOS | 12/12/2025 | 0 | Safari: Only conservative is supported for document rules (though moderate automatically falls back to conservative). Only eager and immediate is supported for list rules.Safari on iOS: Only conservative is supported for document rules (though moderate automatically falls back to conservative). Only eager and immediate is supported for list rules. |
| html.elements.script.type.speculationrules.prefetch 📋 | Safari | 12/12/2025 | Safari on iOS | 12/12/2025 | 0 | |
| html.elements.script.type.speculationrules.referrer_policy 📋 | Safari | 12/12/2025 | Safari on iOS | 12/12/2025 | 0 | |
| html.elements.script.type.speculationrules.relative_to 📋 | Safari | 12/12/2025 | Safari on iOS | 12/12/2025 | 0 | |
| html.elements.script.type.speculationrules.source_optional 📋 | Safari | 12/12/2025 | Safari on iOS | 12/12/2025 | 0 | |
| html.elements.script.type.speculationrules.tag 📋 | Safari | 12/12/2025 | Safari on iOS | 12/12/2025 | 0 | |
| html.elements.script.type.speculationrules.urls 📋 | Safari | 12/12/2025 | Safari on iOS | 12/12/2025 | 0 | |
| html.elements.script.type.speculationrules.where 📋 | Safari | 12/12/2025 | Safari on iOS | 12/12/2025 | 0 | |
| html.elements.template.shadowrootreferencetarget | Safari | 9/15/2025 | Safari on iOS | 9/15/2025 | 0 |