Problems with sending json data to server from javascript using the POST method
Question
I am trying to see the json data I sent to the server using XMLHttpRequest but it seems that the server is not receiving it, when I run the javascript the alert window will pop up but doesn't print anything. Anyone know how to solve this problem? Thanks
On the client side, Java script
var obj = {"action": "nothing"};
var jsonString = "jsonString=" + JSON.stringify(obj);
var xmlhttp = new XMLHttpRequest();
xmlhttp.open("POST","http://myserver/main.php",true);
xmlhttp.setRequestHeader("Content-type","application/json");
xmlhttp.setRequestHeader("Content-Length",jsonString.length);
xmlhttp.onreadystatechange = function()
{
if(xmlhttp.readyState === 4 && xmlhttp.status === 200){
alert(xmlhttp.responseText);
}
}
xmlhttp.send(jsonString);
On the server,php
if(isset($_POST['jsonString']))
echo $_POST['jsonString'];
3 answers
solution1
1 2012-05-15 18:07:09
James' solution works just fine, but if you are looking to send data using the application/json content type then you have to access the data in a different way.
For what you have server side,
if(isset($_POST['jsonString']))
echo $_POST['jsonString'];
change this (like James did):
xmlhttp.setRequestHeader("Content-type","application/json");
to
xmlhttp.setRequestHeader("Content-type","application/x-www-form-urlencoded");
IF YOU WOULD LIKE TO USE THE application/json content type then you must change how you access it server side with:
$json_string = file_get_contents('php://input');
$json_object = json_decode($json_string);
echo $json_object->action;
solution2
1 2011-06-23 04:51:50
You're sending JSON data, but the content-type is set to application/x-www-form-urlencoded . You should either send form/encoded data ( var obj="action=nothing" ) or set the content-type to JSON ( application/json )
solution3
0 2011-06-24 19:20:08
This is working for me:
<html>
<head>
<script src='json.js'></script>
</head>
<body>
<script>
var obj = {"action": "nothing"};
var jsonString = "jsonString=" + JSON.stringify(obj);
var xmlhttp = new XMLHttpRequest();
xmlhttp.open("POST","whereIPutThePHP.php",true);
xmlhttp.setRequestHeader("Content-type","application/x-www-form-urlencoded");
xmlhttp.setRequestHeader("Content-Length",jsonString.length);
xmlhttp.onreadystatechange = function()
{
if(xmlhttp.readyState === 4 && (xmlhttp.status === 200)){
alert(xmlhttp.responseText);
}
}
xmlhttp.send(jsonString);
</script>
</body>
</html>
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