PHP processing JSON_ Decode() parses JSON stringify

      We often use JSON.stringify() Save some data , Then it needs to be in php Read from , But in PHP When receiving the data of this parameter , Use json_decode() But it can't be parsed .
So the problem is , Why? json_decode() analysis JSON.stringify Why NULL.
resolvent ：
When you use JSON stringify when , First in json_decode Before using html_entity_decode.
Code example ：
$tempData = html_entity_decode($tempData);
$cleanData = json_decode($tempData);

html_entity_decode(string,flags,character-set) Function HTML Entity to character , yes htmlentities() Inverse function of function .
string      It's necessary . Specify the string to decode .
flags    
Optional . Specify how quotation marks are handled and which document type to use .
Available quote types ：
    ENT_COMPAT - Default . Decode only double quotes .
    ENT_QUOTES - Decode double and single quotation marks .
    ENT_NOQUOTES - Don't decode any quotes .
The type of document used in addition to flags：
    ENT_HTML401 - Default . As HTML 4.01 Processing code .
    ENT_HTML5 - As HTML 5 Processing code .
    ENT_XML1 - As XML 1 Processing code .
    ENT_XHTML - As XHTML Processing code .

character-set    
Optional . A string value , Specify the character set to use .
Allowed value ：
    UTF-8 - Default .ASCII Compatible with multi byte 8 position Unicode
    ISO-8859-1 - Western Europe
    ISO-8859-15 - Western Europe （ Add the euro symbol + ISO-8859-1 Missing French and Finnish letters in ）
    cp866 - DOS special Cyrillic Character set
    cp1251 - Windows special Cyrillic Character set
    cp1252 - Windows Dedicated Western European character set
    KOI8-R - Russian
    BIG5 - Traditional Chinese , Mainly used in Taiwan
    GB2312 - Simplified Chinese , National standard character set
    BIG5-HKSCS - With Hong Kong expansion Big5
    Shift_JIS - Japanese
    EUC-JP - Japanese
    MacRoman - Mac The character set used by the operating system
notes ： stay PHP 5.4 Previous version , Unrecognized character sets will be ignored and replaced by ISO-8859-1 replace . since PHP 5.4 rise , Unrecognized character sets will be ignored and replaced by UTF-8 replace .