php form isset validation - php

Question

i have been trying to implement isset form validation on a signup form i am developing for my site......
basically i need all fields filled in correctly or form wont $_post.....
as im posting to self (form action="") i will need my form to reload and display error messages above form if not filled correctly....
here is my form code ....
<?php
if(!isset($_POST['submit'])) {
echo '
<form action="" method="post" name="signup">
<table border="1" width="100%">
<tr><td>
<p style="text-align: right;">First Name: </p>
</td><td>
<input name="first_name" type="text" maxlength="25">
</td></tr>
<tr><td>
<p style="text-align: right;">Last Name: </p>
</td><td>
<input name="last_name" type="text" maxlength="25">
</td></tr>
<tr><td>
<p style="text-align: right;">Desired Username: </p>
</td><td>
<input name="username" type="text" maxlength="25">
</td></tr>
<tr><td>
<p style="text-align: right;">Password: </p>
</td><td>
<input name="password" type="password" maxlength="25">
</td></tr>
<tr><td>
<p style="text-align: right;">Confirm Password: </p>
</td><td>
<input name="confpassword" type="password" maxlength="25">
</td></tr>
<tr><td>
<p style="text-align: right;">Date Of Birth: </p>
</td><td>
<select name="dob_day">
<option value="000">Day</option>
<option value="01">01</option>
<option value="02">02</option>
<option value="03">03</option>
<option value="04">04</option>
<option value="05">05</option>
<option value="06">06</option>
<option value="07">07</option>
<option value="08">08</option>
<option value="09">09</option>
<option value="10">10</option>
<option value="11">11</option>
<option value="12">12</option>
<option value="13">13</option>
<option value="14">14</option>
<option value="15">15</option>
<option value="16">16</option>
<option value="17">17</option>
<option value="18">18</option>
<option value="19">19</option>
<option value="20">20</option>
<option value="21">21</option>
<option value="22">22</option>
<option value="23">23</option>
<option value="24">24</option>
<option value="25">25</option>
<option value="26">26</option>
<option value="27">27</option>
<option value="28">28</option>
<option value="29">29</option>
<option value="30">30</option>
<option value="31">31</option>
</select>
<select name="dob_month">
<option value="000">Month</option>
<option value="january">January</option>
<option value="february">February</option>
<option value="march">March</option>
<option value="april">April</option>
<option value="may">May</option>
<option value="june">June</option>
<option value="july">July</option>
<option value="august">August</option>
<option value="september">September</option>
<option value="october">October</option>
<option value="november">November</option>
<option value="december">December</option>
</select>
Year:
<input name="dob_year" type="text" maxlength="4" size="10" value="eg: 1964">
</td></tr>
<tr><td>
<p style="text-align: right;">Email Address: </p>
</td><td>
<input name="email" type="text" maxlength="50">
</td></tr>
<tr><td>
<p style="text-align: right;">Gender: </p>
</td><td>
Male: <input type="radio" name="gender" value="male" />
Female: <input type="radio" name="gender" value="female" />
</td></tr>
</table><p>
<center><input type="submit" name="submit" value=" Sign-Up "></center>
</font>
';}
else
{
echo "Form Submitted";
}
?>
i know this form code looks garbled, and i hate messy code, but i had to truncate it to post on here, or i would be typing 4 spaces before hundreds of code lines lol
if anyone can come up with a solution to this (would presume pretty simple but cannot figure how to code it") i will be very greatful again :D
thanks guys
:bow: STACK EXCHANGE ALL THE WAY :bow:

Answer 1

else
{
$accept=true;
if(!isset($_POST["value1"])){
$accept=false;
$_SESSION["error"] .= "Please fill in value1\n";
}
//.... Other values
if(!$accept){
header("Location: Current file name"); //Check if the session has the error value filled in and display it on the form.
exit;
}
echo "Form Submitted";
}
Full example:
<?php
session_start();
if(!isset($_POST['submit'])) {
echo '
<form action="" method="post" name="signup">
<table border="1" width="100%">
<tr><td colspan="2">' . $_SESSION['error'] . ' </td></tr>
<tr><td>
<p style="text-align: right;">First Name: </p>
</td><td>
<input name="first_name" type="text" maxlength="25">
</td></tr>
<tr><td>
<p style="text-align: right;">Last Name: </p>
</td><td>
<input name="last_name" type="text" maxlength="25">
</td></tr>
<tr><td>
<p style="text-align: right;">Desired Username: </p>
</td><td>
<input name="username" type="text" maxlength="25">
</td></tr>
<tr><td>
<p style="text-align: right;">Password: </p>
</td><td>
<input name="password" type="password" maxlength="25">
</td></tr>
<tr><td>
<p style="text-align: right;">Confirm Password: </p>
</td><td>
<input name="confpassword" type="password" maxlength="25">
</td></tr>
<tr><td>
<p style="text-align: right;">Date Of Birth: </p>
</td><td>
<select name="dob_day">
<option value="000">Day</option>
<option value="01">01</option>
<option value="02">02</option>
<option value="03">03</option>
<option value="04">04</option>
<option value="05">05</option>
<option value="06">06</option>
<option value="07">07</option>
<option value="08">08</option>
<option value="09">09</option>
<option value="10">10</option>
<option value="11">11</option>
<option value="12">12</option>
<option value="13">13</option>
<option value="14">14</option>
<option value="15">15</option>
<option value="16">16</option>
<option value="17">17</option>
<option value="18">18</option>
<option value="19">19</option>
<option value="20">20</option>
<option value="21">21</option>
<option value="22">22</option>
<option value="23">23</option>
<option value="24">24</option>
<option value="25">25</option>
<option value="26">26</option>
<option value="27">27</option>
<option value="28">28</option>
<option value="29">29</option>
<option value="30">30</option>
<option value="31">31</option>
</select>
<select name="dob_month">
<option value="000">Month</option>
<option value="january">January</option>
<option value="february">February</option>
<option value="march">March</option>
<option value="april">April</option>
<option value="may">May</option>
<option value="june">June</option>
<option value="july">July</option>
<option value="august">August</option>
<option value="september">September</option>
<option value="october">October</option>
<option value="november">November</option>
<option value="december">December</option>
</select>
Year:
<input name="dob_year" type="text" maxlength="4" size="10" value="eg: 1964">
</td></tr>
<tr><td>
<p style="text-align: right;">Email Address: </p>
</td><td>
<input name="email" type="text" maxlength="50">
</td></tr>
<tr><td>
<p style="text-align: right;">Gender: </p>
</td><td>
Male: <input type="radio" name="gender" value="male" />
Female: <input type="radio" name="gender" value="female" />
</td></tr>
</table><p>
<center><input type="submit" name="submit" value=" Sign-Up "></center>
</font>
';}
else
{
$accept=true;
if(!isset($_POST["first_name"])){
$accept=false;
$_SESSION["error"] .= "Please fill in your first name.<br />";
}
//.... Other values
if(!$accept){
header("Location: " . $_SERVER["PHP_SELF"]); //Check if the session has the error value filled in and display it on the form.
exit;
}
echo "Form Submitted";
}
?>

Answer 2

Form validation can be done using javascript.
HTML
<input type="submit" onclick="return validate();" />
JAVASCRIPT
<script type="text/javascript">
function validate()
{
if(document.getElementsByName('username') == "")
{
alert("Please Enter username");
return false;
}
...
}
</script>

Answer 3

all your code currently does it verify someone clicked the submit button, it doesnt actually verify they entered valid values. Understand that isset doesnt check that a variable has a value, just that the variable exists, which it will since all form elements will exist in the post array regardless of what, if any value is posted.
2 tips for you:
1) use a foreach loop to evaluate each element of the post array. You can create a seperate array of expected value conditions to check against in the loop. There are plenty of ready to use validation filter scripts out there you can just plug in to check that your expected value is char, int, float etc. PLEASE always validate your user input before inserting into your database or your asking for SQL injection attack.
2) use print_r($_POST) to debug your form submissions if you dont understand what exactly is being submitted....
also I find its easier to put the PHP at the top of the file and leave the html below. If you arent using PHP values to prefill out form values, there is no need to echo your html. This makes it much easier to edit your html... observe the php tags in the start and end of the else statement:
<?php
if(isset($_POST['submit'])) {
echo "Form Submitted";
}
else{ ?>
<form action="" method="post" name="signup">
<table border="1" width="100%">
<tr><td>
<p style="text-align: right;">First Name: </p>
</td><td>
<input name="first_name" type="text" maxlength="25">
</td></tr>
<tr><td>
<p style="text-align: right;">Last Name: </p>
</td><td>
<input name="last_name" type="text" maxlength="25">
</td></tr>
<tr><td>
<p style="text-align: right;">Desired Username: </p>
</td><td>
<input name="username" type="text" maxlength="25">
</td></tr>
<tr><td>
<p style="text-align: right;">Password: </p>
</td><td>
<input name="password" type="password" maxlength="25">
</td></tr>
<tr><td>
<p style="text-align: right;">Confirm Password: </p>
</td><td>
<input name="confpassword" type="password" maxlength="25">
</td></tr>
<tr><td>
<p style="text-align: right;">Date Of Birth: </p>
</td><td>
<select name="dob_day">
<option value="000">Day</option>
<option value="01">01</option>
<option value="02">02</option>
<option value="03">03</option>
<option value="04">04</option>
<option value="05">05</option>
<option value="06">06</option>
<option value="07">07</option>
<option value="08">08</option>
<option value="09">09</option>
<option value="10">10</option>
<option value="11">11</option>
<option value="12">12</option>
<option value="13">13</option>
<option value="14">14</option>
<option value="15">15</option>
<option value="16">16</option>
<option value="17">17</option>
<option value="18">18</option>
<option value="19">19</option>
<option value="20">20</option>
<option value="21">21</option>
<option value="22">22</option>
<option value="23">23</option>
<option value="24">24</option>
<option value="25">25</option>
<option value="26">26</option>
<option value="27">27</option>
<option value="28">28</option>
<option value="29">29</option>
<option value="30">30</option>
<option value="31">31</option>
</select>
<select name="dob_month">
<option value="000">Month</option>
<option value="january">January</option>
<option value="february">February</option>
<option value="march">March</option>
<option value="april">April</option>
<option value="may">May</option>
<option value="june">June</option>
<option value="july">July</option>
<option value="august">August</option>
<option value="september">September</option>
<option value="october">October</option>
<option value="november">November</option>
<option value="december">December</option>
</select>
Year:
<input name="dob_year" type="text" maxlength="4" size="10" value="eg: 1964">
</td></tr>
<tr><td>
<p style="text-align: right;">Email Address: </p>
</td><td>
<input name="email" type="text" maxlength="50">
</td></tr>
<tr><td>
<p style="text-align: right;">Gender: </p>
</td><td>
Male: <input type="radio" name="gender" value="male" />
Female: <input type="radio" name="gender" value="female" />
</td></tr>
</table><p>
<center><input type="submit" name="submit" value=" Sign-Up "></center>
</font>
<?php } ?>

Answer 4

<html>
<body>
<form action="<?php $_PHP_SELF ?>" method="GET">
Name: <input type="text" name="name" />
Age: <input type="text" name="age" />
<input type="submit" name="submit" value="submit"/>
</form>
<?php
if (isset($_GET['submit']))
{
$name = $_GET['name'];
$age = $_GET['age'];
echo "Welcome ".$name."<br />" ;
echo "You are ".$age." years old<br/>";
}
else
{
echo "enter the appropriate details";
exit();
}
?>
</body>
</html>

Answer 5

<html>
<body>
if
(isset($_GET['actie']) && $_GET['actie']== "registreren") {
//registreerformulier
echo "<form method='post' action='".$_SERVER['PHP_SELF']."?actie=aanmaken'>
Voornaam <input name='voornaam' type='text' /> <br />
Familienaam <input name='familienaam' type='text' /> <br />
Wachtwoord <input name='wachtwoord' type='password' /> <br />
Wachtwoord-controle <input name='wachtwoordControle' type='password' /> <br />
<input name='submit' type='submit' value='Maak gebruiker aan' />
</form>";
</body>
</html>