# Getting Chrome Extension User ID in Any Tab
This guide shows you how to access the Chrome extension user ID from any web page or tab.
## Method 1: Automatic Content Script (Recommended)
The content script automatically injects the user ID into every page. You can access it in several ways:
### A. Global Window Variable
```javascript
// Check if user ID is available
if (window.chromeExtensionUserId) {
console.log('User ID:', window.chromeExtensionUserId);
} else {
console.log('User ID not available yet');
}
```
### B. Session Storage
```javascript
// Get user ID from session storage
const userId = sessionStorage.getItem('chromeExtensionUserId');
if (userId) {
console.log('User ID from storage:', userId);
}
```
### C. Event Listener (Best for Dynamic Loading)
```javascript
// Listen for user ID ready event
window.addEventListener('chromeExtensionUserIdReady', function(event) {
const userId = event.detail.userId;
console.log('User ID received:', userId);
// Your code here
});
// Also check if it's already available
if (window.chromeExtensionUserId) {
console.log('User ID already available:', window.chromeExtensionUserId);
}
```
## Method 2: User ID Helper API
If the automatic injection doesn't work, you can use the helper API:
### A. Simple Promise-based Access
```javascript
// Get user ID asynchronously
window.getChromeExtensionUserId().then(userId => {
if (userId) {
console.log('User ID:', userId);
// Your code here
} else {
console.log('No user ID available');
}
});
```
### B. Synchronous Access (if already loaded)
```javascript
// Get user ID synchronously (only if already available)
const userId = window.getChromeExtensionUserIdSync();
if (userId) {
console.log('User ID (sync):', userId);
}
```
### C. Callback-based Access
```javascript
// Execute callback when user ID becomes available
window.ChromeExtensionUserID.onUserIdReady(function(userId) {
console.log('User ID ready:', userId);
// Your code here
});
```
## Method 3: Manual Injection
You can manually inject the user ID helper into any tab:
### From Extension Popup or Background Script
```javascript
// Inject into current active tab
chrome.runtime.sendMessage({ type: 'injectUserIdHelper' }, (response) => {
if (response.success) {
console.log('User ID helper injected:', response.message);
} else {
console.error('Failed to inject:', response.error);
}
});
// Inject into specific tab
chrome.runtime.sendMessage({
type: 'injectUserIdHelper',
tabId: 123
}, (response) => {
console.log('Injection result:', response);
});
```
## Complete Example
Here's a complete example for any web page:
```html
User ID Example
Loading user ID...
```
## User ID Format
The user ID follows this format: `user_{timestamp}_{random}`
Example: `user_1704067200000_abc123def456`
## Troubleshooting
### User ID Not Available
1. **Extension not connected**: Make sure the Chrome extension is connected to the remote server
2. **Content script blocked**: Some sites may block content scripts
3. **Timing issues**: Use event listeners instead of immediate checks
### Manual Injection
If automatic injection fails, you can manually inject the helper:
```javascript
// From browser console or your page script
chrome.runtime.sendMessage({ type: 'injectUserIdHelper' });
```
### Checking Connection Status
```javascript
// Check if extension is available
if (typeof chrome !== 'undefined' && chrome.runtime) {
console.log('Chrome extension context available');
} else {
console.log('No Chrome extension context');
}
```
## Security Notes
- User IDs are anonymous and don't contain personal information
- User IDs persist across browser sessions
- Each Chrome extension instance has a unique user ID
- User IDs are only available when connected to the remote server