Does CSS Attribute selector Work in HTML Email?
The attribute selector (`[attr]`) targets elements with this specific attribute.
Does Attribute selector work in HTML email?
The CSS Attribute selector property is supported in Outlook (Mac / Web), Apple Mail, Samsung Email, Thunderbird, and others. It is NOT supported in Outlook (Windows), ProtonMail. Always include a safe fallback for unsupported clients.
Which Email Clients Support CSS Attribute selector?
CSS support for Attribute selector across email clients
| Email Client | Desktop | Mobile / Web | Notes |
|---|---|---|---|
| Gmail | ~ Partial | ~ Partial | — |
| Outlook (Windows) | ✗ No | ? | — |
| Outlook (Mac / Web) | ✓ Yes | ~ Partial | — |
| Apple Mail | ✓ Yes | ✓ Yes | — |
| Yahoo! Mail | ~ Partial | ~ Partial | — |
| Samsung Email | ? | ✓ Yes | — |
| Thunderbird | ✓ Yes | ? | — |
| ProtonMail | ✗ No | ✗ No | — |
| Fastmail | ✓ Yes | ? | — |
Notes
- #1 Partial. Can not be used with a class selector (`.test[class]`). Must be used solo (`[class]`) or with an element selector (`td[class]`).
- #2 Partial. Only supports `[attr]`, `[attr=value]`, `[attr~=value]`, `[attr|=value]` syntaxes.
- #3 Buggy. A `class="test"` in the HTML is prefixed `class="x_test"`, but an attribute selector stays unprefixed `[class="test"]`.
- #4 Partial. Only supports `[attr=value]` syntax.
- #5 Partial. Only supports `[attr~=value]` syntax. Only `class` as an attribute name is known to be supported.
- #6 Partial. Doesn't work with non Google accounts.
This page reflects support for different syntaxes: `[attr]`, `[attr="value"]`, `[attr~="value"]`, `[attr|="value"]`, `[attr^="value"]`, `[attr$="value"]`, `[attr*="value"]`.
Frequently Asked Questions
Related CSS Properties
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