php header printing full html code on browser-CodePudding

I am making a simple API from PHP.

Code Snippet:

        elseif ($_GET["command"]="verifyconn"){
            header("Content-Type: application/json");
            $data=array("response" => "success");
            echo json_encode($data);
            exit;
        }

Whenever this is executed, I get this response on browser:

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Untitled Document</title>
</head>

<body>
</body>
</html>{"response":"wrong_secret"}

The whole HTML code gets printed on browser. When I remove header("Content-Type: application/json");, it gets fixed and JSON displays but in text. How can I fix it?

CodePudding user response：

It doesn't get really fixed when you remove the content type header, but the HTML part will become "invisible", because the content type will fall back to the default text/html; if you check the source code of the page, you will see it's still there.

The real solution is to search for where the above HTML is printed and remove it.