Preluare sir JSON in PHP de la JavaScript

Curs Ajax

Acest tutorial explica cu exemple de cod cum se poate prelua in PHP un sir JSON transmis cu Ajax din JavaScript.
Se poate folosi unul din urmatoarele doua variante:

Folosind php://input stream

- Documentatie despre PHP I/O streams
In acest caz obiectul JSON e trimis ca sir la php prin ajax cu Content-type application/json.
- Exemplu.
In JavaScript:

<script>
var data ={s1:'marplo.net', s2:'gamv.eu', y:2020};

//jsn_str = json string
function ajaxF(jsn_str) {
 var request = (window.XMLHttpRequest) ? new XMLHttpRequest() : new ActiveXObject('Microsoft.XMLHTTP'); // XMLHttpRequest object

 request.open('POST', 'test.php', true); // set the request

 //sends data as json
 request.setRequestHeader('Content-type', 'application/json');
 request.send(jsn_str);

 // Check request status
 // If the response is received completely, alert response
 request.onreadystatechange =()=>{
 if(request.readyState ==4){
 alert(request.responseText); // marplo.net
 }
 }
}

//converts data object in json string and sends it to php
let jsn = JSON.stringify(data);
ajaxF(jsn);
</script>

In PHP (test.php):

$arr = json_decode(file_get_contents('php://input'), true);
echo $arr['s1'];
exit;

Adaugare sir JSON in variabila $_POST

In acest caz sirul JSON e atasat la un nume (aici "jsn"), si trimis prin ajax cu POST si Content-type application/x-www-form-urlencoded.
- Exemplu.
In JavaScript:

<script>
var data ={s1:'marplo.net', s2:'gamv.eu', y:2020};

//jsn_str = json string
function ajaxF(jsn_str) {
 var request = (window.XMLHttpRequest) ? new XMLHttpRequest() : new ActiveXObject('Microsoft.XMLHTTP'); // XMLHttpRequest object

 request.open('POST', 'test.php', true); // set the request

 //sends data
 request.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
 request.send('jsn='+jsn_str);

 // Check request status
 // If the response is received completely, alert response
 request.onreadystatechange =()=>{
 if(request.readyState ==4){
 alert(request.responseText); // gamv.eu
 }
 }
}

//converts data object in json string and sends it to php
let jsn = JSON.stringify(data);
ajaxF(jsn);
</script>

In PHP (test.php):

$arr = isset($_POST['jsn']) ? json_decode($_POST['jsn'], true) :['s2'=>'default'];
echo $arr['s2'];
exit;

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h2 {
  font-family:"Calibri", sans-serif;
}

var elm_list = document.querySelectorAll("div.cls");
var nr_elms = elm_list.length;       // numar elemente selectate
alert(nr_elms);

$arr =[1, 2, 3, 4);
$arr_sum = array_sum($arr);
echo $arr_sum;       // 10

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