# Determining the Salesforce Style That Users See in JavaScript

If you use a lot of JavaScript in your pages and apps, identifying the Salesforce theme that a user sees in JavaScript code is important. Identifying the current user experience context allows you to correctly manage navigation in your JavaScript code.

The `UITheme.getUITheme()` JavaScript function returns a string containing one of the following values to identify the current user interface theme.

- `Theme1`—Obsolete Salesforce theme
- `Theme2`—Salesforce Classic 2005 user interface theme
- `Theme3`—Salesforce Classic 2010 user interface theme
- `Theme4d`—Modern “Lightning Experience” Salesforce theme
- `Theme4t`—Salesforce mobile app theme
- `Theme4u`—Lightning Console theme
- `PortalDefault`—Salesforce Customer Portal theme
- `Webstore`—AppExchange theme

The string values returned are the same values returned by the Visualforce `$User.UITheme` and `$User.UIThemeDisplayed` global variables.

The following markup checks if the current user experience context is the Lightning Experience theme.

```javascript
function isLightningDesktop() {
  return UITheme.getUITheme === "Theme4d";
}

```

**See Also**

- [Identifying the Salesforce Style Your Users See](/docs/platform/salesforce-pages-developers-guide/guide/pages-styling-salesforce-identifying-theme.md)