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);

}

Answer 1

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);

}

Answer 2

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"
}