Weird character at start of json content type

I'm trying to return json content read from MySQL server. This is supposed to be easy but, there is a 'weird' character that keeps appearing at start of the content. I have two pages for returning content: kcb433.sytes.net/as/test.php?json=true&limit=6&input=d this test.php is from a script written by Timothy Groves, which converts an array to json output http://kcb433.sytes.net/k.php?k=4 this one is supposed to do the same I tried to validate it here jsonformatter.curiousconcept.com but just page 1 gets validated, page 2 says that it does not contain JSON data. If accessed directly both pages has no problems. Then what is the difference, why both don't get validated? Then I found this page jsonformat.com and tried the same thing. Page 1 was ok and page 2 wasn't but, surprisingly the data could be read. At a glance, ``` {"a":"b"} ``` may look good but there is a character in front. According to a hex editor online, this is the value of the string above (instead of 9 values, there are 10): ``` -- 7B 22 61 22 3A 22 62 22 7D ``` The code to echo json in page 2 is: ``` header("Content-Type: application/json"); echo "{\"a\":\"b\"}"; ```