What do I need to escape in my HTML (JSON response)

Answer 1

I used jsonlint to validate your latest example, and the line breaks are what it flagged. When they were removed, it validated.

{
    "rc": "200",
    "m" : "",
    "o": "
asdf<\/a>
0<\/strong>      <\/div>    
444444444<\/p><\/div>
<\/div><\/div>"
}