To resolve the issue with your JSON and HTML integration, follow these key steps:

1. **Escape HTML characters in JSON**:
```json
{
  "name": "John Doe",
  "address": "<div class='address'>123 Main St.<br/>Apt 4B</div>"
}
```

2. **Use `JSON.parse()` instead of `eval()`**:
```javascript
const raw = '{"name": "John Doe", "address": "<div class=\'address\'>123 Main St.<br/>Apt 4B</div>"}';
const parsed = JSON.parse(raw);
document.body.innerHTML = parsed.address;
```

3. **Server-side escaping (if applicable)**:
In languages like PHP:
```php
$address = htmlspecialchars("<div>123 Main St.<br/>Apt 4B</div>", ENT_QUOTES, 'UTF-8');
$json = json_encode(["address" => $address]);
```

4. **HTML injection example**:
```html
<div id="address"></div>
<script>
const data = {"address": "<div>123 Main St.<br/>Apt 4B</div>"};
document.getElementById('address').innerHTML = data.address;
</script>
```

Avoid placing raw HTML directly in JSON values when it will be parsed by JavaScript. Always escape entities or use dedicated templating.