HTML processing instructionsLimited availability
An HTML processing instruction is text enclosed by <? and >, which marks a target for further processing. They may appear anywhere in a document. They are ignored like comments when they're not recognized for a specific purpose.
Not yet supported in all major browsers — check the table and provide a fallback.
Browser support
DesktopChrome
1–149Not supported
150+Supportedsince Jun 30, 2026
Current: 155Edge
12–149Not supported
150+Supportedsince Jul 2, 2026
Current: 154Firefox
✕Not supportedup to 157
Current: 157Safari
✕Not supportedup to 27
Current: 27MobileChrome Android
18–149Not supported
150+Supportedsince Jun 30, 2026
Current: 155Firefox Android
✕Not supportedup to 157
Current: 157Safari iOS
✕Not supportedup to 27
Current: 27How to use
Not supported in Firefox, Safari, Firefox Android, Safari iOS. Use feature detection below and provide a fallback (or a polyfill) for those browsers.
Example
Full syntax and examples are on MDN: getAttribute.
Feature detection
JS · check before using
if ("ProcessingInstruction" in globalThis && "doc_html" in ProcessingInstruction.prototype) {
// ProcessingInstruction.doc_html is available
}Sub-features
Support for each part of the feature (8). The overall table above shows when the whole feature works.
| Sub-feature | Chrome | Edge | Firefox | Safari | Chrome Android | Firefox Android | Safari iOS |
|---|---|---|---|---|---|---|---|
| ProcessingInstruction.doc_html | 150 | 150 | ✕ | ✕ | 150 | ✕ | ✕ |
| ProcessingInstruction.getAttribute | 150 | 150 | ✕ | ✕ | 150 | ✕ | ✕ |
| ProcessingInstruction.getAttributeNames | 150 | 150 | ✕ | ✕ | 150 | ✕ | ✕ |
| ProcessingInstruction.hasAttribute | 150 | 150 | ✕ | ✕ | 150 | ✕ | ✕ |
| ProcessingInstruction.hasAttributes | 150 | 150 | ✕ | ✕ | 150 | ✕ | ✕ |
| ProcessingInstruction.removeAttribute | 150 | 150 | ✕ | ✕ | 150 | ✕ | ✕ |
| ProcessingInstruction.setAttribute | 150 | 150 | ✕ | ✕ | 150 | ✕ | ✕ |
| ProcessingInstruction.toggleAttribute | 150 | 150 | ✕ | ✕ | 150 | ✕ | ✕ |