Php's json_decode function returns null

You can use the return value obtained by The json_last_error () function to help us determine the cause of the problem.

If the error JSON_ERROR_SYNTAX (Syntax error) is displayed, the json string format is incorrect.

You can troubleshoot the error in the following ways:

1. json strings must contain double quotation marks

The code is as follows:	Copy code
$ Output = str_replace ("'",' "', $ output ); 2. The json string must be UTF-8 encoded. $ Output = iconv ('gbk', 'utf8', $ output );

3. There cannot be redundant commas, for example, [,]
Replace with regular expressions, preg_replace ('/, \ s * ([\]}])/M',' $ 1', $ output)