Ajax无法通过POST

I have a form and I need to POST data to a compute.php file. I have to pass the content of two select fields, named select_1 and select_2. My fiire button has a onclick='go()' call.

My script code is as follows:

function go() {
var sel_1 = document.getElementById('select_1').value;
var sel_2 = document.getElementById('select_2').value;
$.ajax({
    type: "POST",
    url: "compute.php",
    data: "select_1=" + sel_1 + "&select_2=" + sel_2,
    dataType: "text",
    success: function(data,status)
      /* ------------ for debug I have an alert with a response ---- */
      {
        alert("passed data are: " + data + "
Status: " + status);
      },
    error: function(data,status)
      {
        alert("passed data are: " + data + "
Status: " + status);
      }
    });
}

On the php side my compute.php file has code as follows:

$selection_1 = $_POST["select_1"];
$selection_2 = $_POST["select_2"];

$sqladd = "INSERT INTO table SET column_1 = '$selection_1', column_2 = '$selection_2';";
if (mysqli_query($conn, $sqladd)) {
   $resultadd= mysqli_query($conn, $sqladd);
   // ------- then for debug purpose
   echo "inserted row with col_1 --->" . $selection_1 . "<--- and col_2 --->" . $selection_2;
} else {
   // ------- either, still for debug purpose
   echo "not inserted. ";
   echo "Error: " . mysqli_error($conn);
}

Now the alert box shows that js has correctly got the values of the two select fields, and I also get back a success status, but my debug echo from compute.php shows empty values for selection_1 and selection_2, and the table row is inserted but in the inserted row the table columns are empty. Apache log shows two notices: PHP Notice: Undefined index: select_1 in compute.php and PHP Notice: Undefined index: select_2 in compute.php. So PHP doesn't receives the two POST values. What am I doing wrong? I have the following rules and conditions in .htaccess:

RewriteCond %{THE_REQUEST} ^[A-Z]{3,}\s([^.]+)\.php [NC]
RewriteRule ^ %1 [R,L,NC]
RewriteCond %{REQUEST_FILENAME}.php [NC]
RewriteRule ^ %{REQUEST_URI}.php [L]

Can they block POST? If yes, how can I get the same result without blocking POST? I need externally redirect /dir/foo.php to /dir/foo and to internally redirect /dir/foo to /dir/foo.php.

Try modifying your go function to be like this:

function go() {
var sel_1 = document.getElementById('select_1').value;
var sel_2 = document.getElementById('select_2').value;
$.ajax({
    method: "post",
    url: "compute.php", 
    data: {"select_1":sel_1 , "select_2":sel_2},
    success: function(data,status)
      /* ------------ for debug I have an alert with a response ---- */
      {
        alert("passed data are: " + data + "
Status: " + status);
      },
    error: function(data,status)
      {
        alert("passed data are: " + data + "
Status: " + status);
      }
    });
}

function go() {
var sel_1 = $('#select_1').val();
var sel_2 = $('#select_2').val();
$.post("compute.php", {
    select_1 : sel_1,
    select_2 : sel_2
    }, function (answ) {
    console.log(answ);
  });
}

Modify your data object in ajax of go function data: {"select_1": sel_1, "select_2": sel_2}

Your select box must lock like that

<select id="select_1">
<option></option></select>
</select>

I think your selected boxes are named select_1 and select_2, but you must set the id not the name.

p.s if you use the id please paste you html code.

POST was blocked by .htaccess instructions as above. Changed and now POST is working from html, but still problems in making js/ajax/jquery work for posting my data to compute.php