Cleans up HTML and ensure that only a very limited subset of tags/attributes are allowed.
Any other HTML will be entity-encoded.
| Tag | Allowed attributes |
|---|---|
| code | - |
| blockquote | - |
| h7 | - |
| h6 | - |
| h5 | - |
| h4 | - |
| h3 | - |
| h2 | - |
| h1 | - |
| ol | - |
| u | - |
| li | - |
| ul | - |
| pre | - |
| p | - |
| i | - |
| b | - |
| br | - |
| a | href,name,rel |
| hr | - |
| img | alt,height,src,width |