insert HTML form data into SQL

<table width="300" border="0" align="center" cellpadding="0" cellspacing="1">
   <tr>
      <td>
         <form name="form1" method="post" action="insert_ac.php">
         <table width="100%" border="0" cellspacing="1" cellpadding="3">
            <tr>
               <td colspan="3">Insert Data Into mySQL Database </td>
            </tr>
            <tr>
               <td width="71">Name</td>
               <td width="6">:</td>
               <td width="301"><input name="name" type="text" id="name"></td>
            </tr>
            <tr>
               <td>Lastname</td>
               <td>:</td>
               <td><input name="lastname" type="text" id="lastname"></td>
            </tr>
            <tr>
               <td>Email</td>
               <td>:</td>
               <td><input name="email" type="text" id="email"></td>
            </tr>
            <tr>
               <td colspan="3" align="center"><input type="submit" name="Submit" value="Submit"></td>
            </tr>
         </table>
         </form>
      </td>
   </tr>
</table>

<?php
insert_ac.php
$host="192.168.1.2"; // Host name
$username="xyz"; // Mysql username
$password="abc"; // Mysql password
$db_name="test"; // Database name
$tbl_name="test_mysql"; // Table name

// Connect to server and select database.
mysql_connect("$host", "$username", "$password")or die("cannot connect");
mysql_select_db("$db_name")or die("cannot select DB");

// Get values from form
$name=$_POST['name'];
$lastname=$_POST['lastname'];
$email=$_POST['email'];

// Insert data into mysql
$sql="INSERT INTO $tbl_name(name, lastname, email)VALUES('$name', '$lastname', '$email')";
$result=mysql_query($sql);

// if successfully insert data into database, displays message "Successful".
if($result){
echo "Successful";
echo "<BR>";
echo "<a href='insert.php'>Back to main page</a>";
}
else {
echo "ERROR";
}
?>

<?php
// close connection
mysql_close();
?>