Added comment preview functionality to user pages. It works by passing the comment...

Added comment preview functionality to user pages. It works by passing the comment's value as a JSON string to a new handler that lives at /ajax/comment/preview. The query string is decoded, unquoted, and has its leading and trailing quotes removed to match the input that cleaned_markdown_conversion expects.

It does this in real time with a 500ms lag by using a timer. Initially I tried the onChange handler but you need to lose focus for that to process. The javascript timer is only invoked if the add comment button is pressed. A request is only sent if the comment box is not empty and the current value is not the same as the last value.