Checking the entered data

I have a registration code:

<?php
$submit = strip_tags($_POST['submit']);
$username = strip_tags($_POST['username']);
$password = strip_tags($_POST['password']);
$repeatpassword = strip_tags($_POST['repeatpassword']);
$email = strip_tags($_POST['email']);
$date = date("Y-m-d");
$avatarka = $_GET['avatarka'];
if ($submit)
{
 // check for existans
if($username&&$password&&$repeatpassword&&$email&&$startpoke)
{
if ($password==$repeatpassword)
{
//check name
if(strlen($username)>15||strlen($username)<4)
{
echo "    4  15 !";
}
else
{
 //check password
if (strlen($password)>25||strlen($password)<6)
{
echo "    6  25 ";
}
else
{
 //encrypt password
$password =$password;
$repeatpassword =$repeatpassword;
//open database
$ip = $_SERVER['REMOTE_ADDR'];
$db = mysql_connect("","","")or die(mysql_error());
mysql_select_db("")or die(mysql_error());
//  
die ("
 
");
}
}
}
else
echo "  !";
}
else
echo " <b></b> ";
}
?>

I checked everything, but the registration template also has checkbox, avatarka:

<input name='avatarka' type='radio' value='7' class='checkbox' >

How to insert a check for entering an avatar into the php code. Thanks in advance.


Answer 1, authority 100%

if(!empty($avatarka)){
// 
}

not?

BUT there is more in the registration template
checkbox, avatar:

this is not a checkbox, this is a radio