I am using jquery, JSON, and AJAX for a comment system. I am curious, is there a size limit on what you can send through/store with JSON? Like if a user types a large amount and I send it through JSON is there some sort of maximum limit? 

Also can any kind of text be sent through JSON. for example sometime I allow users to use html, will this be ok?
['https://Stackoverflow.com/questions/1262376', 'https://Stackoverflow.com', 'https://Stackoverflow.com/users/143030/']
It depends on the implementation of your JSON writer/parser. Microsoft's DataContractJsonSerializer seems to have a hard limit around 8kb (8192 I think), and it will error out for larger strings.

Edit:
We were able to resolve the 8K limit for JSON strings by setting the MaxJsonLength property in the web config as described in this answer: <https://stackoverflow.com/a/1151993/61569>
The maximum length of JSON strings. The default is 2097152 characters, which is equivalent to 4 MB of Unicode string data.

Refer below URL

<https://learn.microsoft.com/en-us/dotnet/api/system.web.script.serialization.javascriptserializer.maxjsonlength?view=netframework-4.7.2>