How to send a string to php with POST [duplicate]

Question

I'm sending a string via xmlhttp in javascript using the following code:

 function SendPHP(str, callback) { if (window.XMLHttpRequest) { // code for IE7+, Firefox, Chrome, Opera, Safari xmlhttp = new XMLHttpRequest(); } else { // code for IE6, IE5 xmlhttp = new ActiveXObject("Microsoft.XMLHTTP"); } xmlhttp.onreadystatechange = function () { if (xmlhttp.readyState == 4 && xmlhttp.status == 200) { callback(xmlhttp.responseText); //invoke the callback } } xmlhttp.open("GET", "testpost.php?q=" + encodeURIComponent(str), true); xmlhttp.send(); }

and some test php:

$q = $_GET['q']; echo $q;

That worked fine until I started sending a larger string in which case I get the "HTTP/1.1 414 Request-URI Too Long" error.

After a bit of research I found out I need to use "POST" instead. So I changed it to:

xmlhttp.open("POST", "sendmail.php?q=" + str, true);

And:

$q = $_POST['q']; echo $q;

But this does not echo anything when using POST. How can I fix it so it works like when I was using GET but so it can handle a large string of data?

edit I'm now trying it with:

function testNewPHP(str){ xmlhttp = new XMLHttpRequest(); str = "q=" + encodeURIComponent(str); alert (str); xmlhttp.open("POST","testpost.php", true); xmlhttp.onreadystatechange=function(){ if (xmlhttp.readyState == 4){ if(xmlhttp.status == 200){ alert (xmlhttp.responseText); } } }; xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded"); xmlhttp.send(str); }

You do not POST variables using url parameters, they are sent through the send method — Patrick Evans
– Patrick Evans, Commented Apr 11, 2014 at 20:06
I'm basically using it to send a CSV file turned into a string to my php script which does some processing on it. So it's just a long string that needs to be processed by the php script. — dlofrodloh
– dlofrodloh, Commented Apr 11, 2014 at 20:08
@Saman I read that before to figure out I need to use POST instead of GET, but it doesn't say the difference on how to use it vs GET. — dlofrodloh
– dlofrodloh, Commented Apr 11, 2014 at 20:12

souslov · Accepted Answer · 2014-04-11 22:52:34Z

You should not provide your href with URL parameters, instead of this you should send() them. For addition, you should always encode your parameters with encodeURIComponent() (At least when your request is using the Content-type "application/x-www-form-urlencoded").

your javascript function :

function testNewPHP(){ var str = "This is test"; xmlhttp = new XMLHttpRequest(); str = "q=" + encodeURIComponent(str); alert (str); xmlhttp.open("POST","testpost.php", true); xmlhttp.onreadystatechange=function(){ if (xmlhttp.readyState == 4){ if(xmlhttp.status == 200){ alert (xmlhttp.responseText); } } }; xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded"); xmlhttp.send(str); }

Couldn't let that mistake get in the way of your great answer. Heh.
The str string in my code is the contents of a CSV file. In this answer is it overwritten with something? I'm not sure I understand the json part.

souslov · Accepted Answer · 2014-04-11 22:32:03Z

javascript :

 function testNewPHP(){ var str = "This is test"; xmlhttp = new XMLHttpRequest(); str = "q=" + encodeURIComponent(str); alert (str); xmlhttp.open("POST","testpost.php", true); xmlhttp.onreadystatechange=function(){ if (xmlhttp.readyState == 4){ if(xmlhttp.status == 200){ alert (xmlhttp.responseText); } } }; xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded"); xmlhttp.send(str); }

testpost.php in your home directory :

<?php var_dump($_POST);

OUTPUT :

array(1) { ["q"]=> string(12) "This is test" }

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How to send a string to php with POST [duplicate]

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