XFrameOptionsMode

An enum representing the `X-Frame-Options` modes that can be used for client-side `https://developers.google.com/apps-script/reference/html/html-service` scripts. These values can be accessed from `https://developers.google.com/apps-script/reference/html/html-service#XFrameOptionsMode`,
and set by calling `https://developers.google.com/apps-script/reference/html/html-output#setXFrameOptionsMode(XFrameOptionsMode)`.

To call an enum, you call its parent class, name, and property. For example, `
HtmlService.XFrameOptionsMode.ALLOWALL`.

Setting `XFrameOptionsMode.ALLOWALL` lets any site iframe the page, so the developer
should implement their own protection against clickjacking.

If a script does not set an `X-Frame-Options` mode, Apps Script uses `DEFAULT`
mode as the default.

```javascript
// Serve HTML with no X-Frame-Options header (in Apps Script server-side code).
const output = HtmlService.createHtmlOutput('<b>Hello, world!</b>');
output.setXFrameOptionsMode(HtmlService.XFrameOptionsMode.ALLOWALL);
```

### Properties

| Property | Type | Description |
|---|---|---|
| `ALLOWALL` | `Enum` | No `X-Frame-Options` header is set. This lets any site iframe the page, so the developer should implement their own protection against clickjacking. |
| `DEFAULT` | `Enum` | Sets the default value for the `X-Frame-Options` header, which preserves normal security assumptions. If a script does not set an `X-Frame-Options` mode, Apps Script uses this mode as the default. |