无法将数据发布到PHP

I am trying to post some data to the php but i could not send anything and see where the problem is.The codes looks fine to me.In other words, i could not reach inside of if statement.Codes;

<form method="post" action="home.php" name="home" id="home">           
    <label for="in_come">enter something: </label><input type="text" name="in_come" id="in_come" /><br/>

<?php
echo "outside if";
if(isset($_POST['in_come']))
{
    echo "inside if";
    $income = $_POST['in_come']; 

    $registerquery = mysql_query("INSERT INTO income (income) VALUES ('".$in_come."')");   
    if ($registerquery)
    {
        echo "sended";
    }                           
}       
?>

if echo "inside if"; is not working, try

if (isset($_POST['in_come']) && ($_POST['in_come'] != ""))

instead of

if(isset($_POST['in_come']))

You assign $income but later you use $in_come in your query

$income = $_POST['in_come']; 

$registerquery = mysql_query("INSERT INTO dersler (income) VALUES ('".$in_come."')");
//-----------------------------------------------------------------^^^^^^^^^^^^^^^

Incidentally, this won't hurt your PHP, but the you also have used <label for='income'> while the input's id is actually id='in_come'.

To debug the contents of your POST and verify that $_POST['in_come'] is set, use:

var_dump($_POST);