> For the complete documentation index, see [llms.txt](https://developers.weglot.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developers.weglot.com/cms/wordpress/filters/language-switcher-hooks.md).

# Language Switcher Hooks

WordPress Filters relating to the language switcher scripts served by the Weglot CDN

When your project uses a switcher template, Weglot loads the corresponding script from `cdn.weglot.com`:

```html
<script id="weglot-switcher-underline_edge-js" src="https://cdn.weglot.com/switchers/underline_edge.812411f0d5ee3549e026c42e4ccb6166888df6a4.min.js"></script>
```

{% hint style="info" %}
Subresource Integrity on the switcher scripts, and the filter that disables it, are available since Weglot 6.3. Earlier versions render the script tag without an `integrity` attribute.
{% endhint %}

#### Integrity of the scripts served by the CDN

The long hexadecimal string in the filename is a **cache-busting** identifier. It tells the CDN which build to serve, and it lets that file be cached forever — the CDN answers with `cache-control: public, max-age=31536000`, and a new build always gets a new filename. It does **not** let the browser verify the bytes it received.

That verification is what [Subresource Integrity](https://developer.mozilla.org/en-US/docs/Web/Security/Subresource_Integrity) (SRI) provides, and Weglot enables it for you. Alongside each template hash, `https://cdn.weglot.com/switchers/versions.json` publishes a SHA-384 digest:

```json
{
  "name": "underline_edge",
  "hash": "812411f0d5ee3549e026c42e4ccb6166888df6a4",
  "integrity": "sha384-CZNjAG4i1RQE7vG/pwnVcrKXI07L/LiE1Yh74wEJ7apQRJDDTLqMguiMHo+rSxTf"
}
```

The plugin reads that digest and renders it on the tag, together with the `crossorigin` attribute SRI requires:

```html
<script integrity="sha384-CZNjAG4i1RQE7vG/pwnVcrKXI07L/LiE1Yh74wEJ7apQRJDDTLqMguiMHo+rSxTf" crossorigin="anonymous" id="weglot-switcher-underline_edge-js" src="https://cdn.weglot.com/switchers/underline_edge.812411f0d5ee3549e026c42e4ccb6166888df6a4.min.js"></script>
```

The browser then hashes the file it downloaded and refuses to execute it if the digest does not match. You do not have to configure anything — this is on by default.

{% hint style="info" %}
The digest is only attached when the build your project points to is the one currently published in `versions.json`. A project pinned to an older template build gets no `integrity` attribute, because the digest would belong to a different file and the browser would reject a perfectly legitimate script.
{% endhint %}

#### weglot\_switcher\_sri\_enabled

Disables the `integrity` and `crossorigin` attributes on the switcher scripts.

| Argument | Type   | Description                                       |
| -------- | ------ | ------------------------------------------------- |
| $enabled | bool   | `true` by default. Return `false` to disable SRI. |
| $handle  | string | Handle of the script being rendered               |

SRI fails closed: when the digest does not match the bytes received, the browser drops the script entirely and falls back to nothing — the language switcher simply does not appear, and the only trace is a message in the browser console.

In practice this happens when something between Weglot and the browser rewrites the script after the tag has been generated. Front-end optimization plugins that proxy or re-serve external scripts from their own domain are the usual cause.

**Use case**

Turn it off everywhere:

```php
<?php

add_filter( 'weglot_switcher_sri_enabled', '__return_false' );
```

Or only for a given template, keeping the protection on the others:

```php
<?php

add_filter( 'weglot_switcher_sri_enabled', function ( $enabled, $handle ) {
    return 'weglot-switcher-default' !== $handle;
}, 10, 2 );
```

{% hint style="warning" %}
Only reach for this filter if you have confirmed in the browser console that a switcher script is being blocked for an integrity mismatch. Disabling SRI removes the guarantee that the script executed by your visitors is the one Weglot published.
{% endhint %}