JSON response format error - red dot\bullet before response

If your files are encoding with UTF-8, better to encode them with UTF-8 without BOM. This can be easily done through notepad++. The steps are as follows,

1. Open your files in notepad++.
2. Go to Encoding option on the file menu.
3. Then select the option "convert to UTF-8 without BOM".

This may resolve your problem.

I was faced red dots problem in my ajax response I tried a lot of solution but doest work for me after then I tried ob_clean() function I got the solution I solved my problem using ob_clean() inside the constructor method

function __construct()
{
    ob_clean();
}

As mentioned in a comment before: In Chrome, red dots usually represent non-printable special unicode characters.

Please check your server side code to prevent outputting those characters

You need to clear you object buffer on server side. I am using PHP as my server side language and I faced similar problem and the solution was cleaning my buffer using ob_clean();