表单未提交给MySQL数据库

I'm having problems sending data to mysql through a php form.

Here is my form(info.php):

<form action="send.php" class="form-horizontal" method="post" name="application">
<div class="col-md-6">
<select class="form-control" name="title">
<option>Please select </option>
<option>Mr</option>
<option>Mrs</option>
<option>Miss</option>
<option>Ms</option>
</select><br>
<input type="text" class="form-control" placeholder="First name" name="first_name"><br>
<input type="text" class="form-control" placeholder="Surname" name="surname"><br>
Date of birth: <input type ="date" name="dob" class="form-control"><hr>
<h3>Address</h3>
<input type="text" class="form-control" placeholder="House name/ House number"     name="house"><br>
<input type="text" class="form-control" placeholder="Street Name" name="street"><br>
<input type="text" class="form-control" placeholder="Town" name="town"><br>
<input type="text" class="form-control" placeholder="Postcode" name="postcode"><br>
<hr></div>
<div class="col-md-6">
<input type="text" class="form-control" placeholder="Country of birth" name="origin"><br>
<input type="text" class="form-control" placeholder="Mobile/Phone number" name="number">       
<input type="text" class="form-control" placeholder="Email address" name="email"><br>
<input type="hidden" name="plan" value="<? $plan; ?>">
<input type="submit" class="btn btn-success btn-lg" value="Submit application">
<hr>
</form>

Here is send.php:

<?php

 $host="localhost"; // Host name 
 $username="******"; // Mysql username 
 $password="******"; // Mysql password 
 $db_name="*****"; // Database name 
 $tbl_name="*****"; // 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 
 $title=$_POST['title'];
 $first_name=$_POST['first_name'];
 $surname=$_POST['surname'];
 $dob=$_POST["dob'];
 $house=$_POST["house'];
 $street=$_POST["street'];
 $town=$_POST["town'];
 $postcode=$_POST["postcode'];
 $origin=$_POST["origin'];
 $number=$_POST["number'];
 $email=$_POST["email'];
 $plan=$_POST["plan'];



 // Insert data into mysql 
 $sql="INSERT INTO $tbl_name(' ',title, first_name, surname, dob, house, street, town,                postcode, origin, number, email, plan)VALUES(' ','$title', '$first_name', '$surname', '$dob',  '$house', '$street', '$town', '$postcode', '$origin', '$number', 
'$email', '$plan')";
 $sql=mysql_real_escape_string($sql);
 $result=mysql_query($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();
 ?>

When I submit the form to send.php the page goes blank. Does this mean there is something wrong with my database auth?

Thanks in advance.

Your issue is that you never actually close most of your quotes. Your code should look like this:

<?php

 $host="localhost"; // Host name 
 $username="******"; // Mysql username 
 $password="******"; // Mysql password 
 $db_name="*****"; // Database name 
 $tbl_name="*****"; // 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 
 $title=$_POST['title'];
 $first_name=$_POST['first_name'];
 $surname=$_POST['surname'];
 $dob=$_POST['dob'];
 $house=$_POST['house'];
 $street=$_POST['street'];
 $town=$_POST['town'];
 $postcode=$_POST['postcode'];
 $origin=$_POST['origin'];
 $number=$_POST['number'];
 $email=$_POST['email'];
 $plan=$_POST['plan'];



 // Insert data into mysql 
 $sql="INSERT INTO $tbl_name(' ',title, first_name, surname, dob, house, street, town,                postcode, origin, number, email, plan)VALUES(' ','$title', '$first_name', '$surname', '$dob',  '$house', '$street', '$town', '$postcode', '$origin', '$number', 
'$email', '$plan')";
 $sql = mysql_real_escape_string($sql);
 $result=mysql_query($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();
 ?>

try this:

<form action="send.php" class="form-horizontal" method="post" name="application">
<div class="col-md-6">
  <p>
  <select class="form-control" name="title">
    <option value="" disabled>Please select </option>
    <option value="Mr">Mr</option>
    <option value="Mrs">Mrs</option>
    <option value="Miss">Miss</option>
    <option value="Ms">Ms</option>
  </select>
  </p>
  <p><br>
    <input type="text" class="form-control" placeholder="First name" name="first_name">
  </p>
  <p><br>
    <input type="text" class="form-control" placeholder="Surname" name="surname">
  </p>
  <p>Date of birth:<br><input type ="date" name="dob" class="form-control">
  </p>
</div><hr>
<h3>Address</h3>
<p>
  <input type="text" class="form-control" placeholder="House name/ House number"     name="house">
  </p>
<p><br>
  <input type="text" class="form-control" placeholder="Street Name" name="street">
</p>
<p><br>
  <input type="text" class="form-control" placeholder="Town" name="town">
</p>
<p><br>
  <input type="text" class="form-control" placeholder="Postcode" name="postcode"><br>
</p>
<hr>
<div class="col-md-6">
  <p>
    <input type="text" class="form-control" placeholder="Country of birth" name="origin">
    </p>
  <p><br>
    <input type="text" class="form-control" placeholder="Mobile/Phone number" name="number"><form action="send.php" class="form-horizontal" method="post" name="application">
<div class="col-md-6">
  <p>
  <select class="form-control" name="title">
    <option value="" disabled>Please select </option>
    <option value="Mr">Mr</option>
    <option value="Mrs">Mrs</option>
    <option value="Miss">Miss</option>
    <option value="Ms">Ms</option>
  </select>
  </p>
  <p><br>
    <input type="text" class="form-control" placeholder="First name" name="first_name">
  </p>
  <p><br>
    <input type="text" class="form-control" placeholder="Surname" name="surname">
  </p>
  <p>Date of birth:<br><input type ="date" name="dob" class="form-control">
  </p>
</div><hr>
<h3>Address</h3>
<p>
  <input type="text" class="form-control" placeholder="House name/ House number"     name="house">
  </p>
<p><br>
  <input type="text" class="form-control" placeholder="Street Name" name="street">
</p>
<p><br>
  <input type="text" class="form-control" placeholder="Town" name="town">
</p>
<p><br>
  <input type="text" class="form-control" placeholder="Postcode" name="postcode"><br>
</p>
<hr>
<div class="col-md-6">
  <p>
    <input type="text" class="form-control" placeholder="Country of birth" name="origin">
    </p>
  <p><br>
    <input type="text" class="form-control" placeholder="Mobile/Phone number" name="number">
  </p>
  <p>       
    <input type="text" class="form-control" placeholder="Email address" name="email">
  </p>
  <p><br>
    <input type="hidden" name="plan" value="<?php $plan; ?>">
    <input type="submit" class="btn btn-success btn-lg" value="Submit application">
  </p>
</div><hr>
</form>

Here is send.php:

<?php

 $host="localhost"; // Host name 
 $username="******"; // Mysql username 
 $password="******"; // Mysql password 
 $db_name="*****"; // Database name 
 $tbl_name="*****"; // 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 
 $title         =$_POST['title'];
 $first_name    =$_POST['first_name'];
 $surname       =$_POST['surname'];
 $dob           =$_POST['dob'];
 $house         =$_POST['house'];
 $street        =$_POST['street'];
 $town          =$_POST['town'];
 $postcode      =$_POST['postcode'];
 $origin        =$_POST['origin'];
 $number        =$_POST['number'];
 $email         =$_POST['email'];
 $plan          =$_POST['plan'];



 // Insert data into mysql 
 $sql="INSERT INTO `$tbl_name` (title, first_name, surname, dob, house, street, town, postcode, origin, number, email, plan) VALUES ('$title', '$first_name', '$surname', '$dob',  '$house', '$street', '$town', '$postcode', '$origin', '$number','$email', '$plan')";
 //$sql=mysql_real_escape_string($sql);
 $result=mysql_query($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();
 ?>

you are typing the POST all wrong.
yours: $_POST["somename']; // begin with double quote inside and finish with single quote.
Correct: $_POST[""]; or $_POST['somename']; // begin with the same end end with the same. your variables are not assigned correctly because of that.

$sql="INSERT INTO " . $tbl_name . "(`title`, `first_name`, `surname`, `dob`, `house`, `street`, `town`, `postcode`, `origin`, `number`, `email`, `plan`) VALUES($title, $first_name, $surname, $dob, $house, $street, $town, $postcode, $origin, $number, $emai, $plan)";
$sql = mysql_real_escape_string($sql);
$result=mysql_query($sql);