My PHP signup form not working - php

Question

I have created a signup form for my php website using Bootstrap but nothing happens when I click on register. Signup form is made in Bootstrap and it is not working.
<div class="container">
<div class="row">
<div class="col-xs-12 col-sm-8 col-md-6 col-sm-offset-2 col-md-offset-3">
<?php
require_once("company-db.php");
if (!isset($_POST['submit'])) {
?>
<form role="form" action="<?=$_SERVER['PHP_SELF']?>" method="post">
<h2>Please Sign Up <small>It's free and always will be.</small></h2>
<hr class="colorgraph">
<div class="row">
<div class="col-xs-12 col-sm-6 col-md-6">
<div class="form-group">
<input type="text" name="username" id="username" class="form-control input-lg" placeholder="Username" tabindex="1">
</div>
</div>
<div class="col-xs-12 col-sm-6 col-md-6">
<div class="form-group">
<input type="password" name="password" id="password" class="form-control input-lg" placeholder="Password" tabindex="2">
</div>
</div>
</div>
<div class="form-group">
<input type="text" name="company_name" id="company_name" class="form-control input-lg" placeholder="Company Name" tabindex="3">
</div>
<div class="form-group">
<input type="text" name="description" id="description" class="form-control input-lg" placeholder="Company Description" tabindex="4">
</div>
<div class="form-group">
<input type="email" name="email" id="email" class="form-control input-lg" placeholder="Email Address" tabindex="4">
</div>
<div class="row">
<div class="col-xs-4 col-sm-3 col-md-3">
<span class="button-checkbox">
<button type="button" class="btn" data-color="info" tabindex="7">I Agree</button>
<input type="checkbox" name="t_and_c" id="t_and_c" class="hidden" value="1">
</span>
</div>
<div class="col-xs-8 col-sm-9 col-md-9">
By clicking <strong class="label label-primary">Register</strong>, you agree to the Terms and Conditions set out by this site, including our Cookie Use.
</div>
</div>
<hr class="colorgraph">
<div class="row">
<div class="col-xs-12 col-md-6"><input type="submit" value="submit" class="btn btn-primary btn-block btn-lg" tabindex="7"></div>
<div class="col-xs-12 col-md-6">Sign In</div>
</div>
</form>
<?php
} else {
## connect mysql server
$mysqli = new mysqli(DB_HOST, DB_USER, DB_PASS, DB_NAME);
# check connection
if ($mysqli->connect_errno) {
echo "<p>MySQL error no {$mysqli->connect_errno} : {$mysqli->connect_error}</p>";
exit();
}
## query database
# prepare data for insertion
$username = $_POST['username'];
$password = $_POST['password'];
$company_name = $_POST['company_name'];
$description = $_POST['description'];
$email = $_POST['email'];
# check if username and email exist else insert
$exists = 0;
$result = $mysqli->query("SELECT username from companies WHERE username = '{$username}' LIMIT 1");
if ($result->num_rows == 1) {
$exists = 1;
$result = $mysqli->query("SELECT email from companies WHERE email = '{$email}' LIMIT 1");
if ($result->num_rows == 1) $exists = 2;
} else {
$result = $mysqli->query("SELECT email from companies WHERE email = '{$email}' LIMIT 1");
if ($result->num_rows == 1) $exists = 3;
}
if ($exists == 1) echo "<p>Username already exists!</p>";
else if ($exists == 2) echo "<p>Username and Email already exists!</p>";
else if ($exists == 3) echo "<p>Email already exists!</p>";
else {
# insert data into mysql database
$sql = "INSERT INTO `companies` (`id`, `username`, `password`, `company_name`, `description`, `email`)
VALUES (NULL, '{$username}', '{$password}', '{$company_name}', '{$description}', '{$email}')";
if ($mysqli->query($sql)) {
//echo "New Record has id ".$mysqli->insert_id;
echo "<p>Registred successfully!</p>";
} else {
echo "<p>MySQL error no {$mysqli->errno} : {$mysqli->error}</p>";
exit();
}
}
}
?>
</div>
</div>

Answer 1

You don't have a name for your submit button, so this won't get posted.
<input type="submit" value="submit" name="submit"
class="btn btn-primary btn-block btn-lg" tabindex="7">
Give the name attribute and make it set.
Note: You must never rely on Submit button's attribute!
The (!isset($_POST['submit'])) conditional statement depends on the execution of your code.