PHP -- How to replace string value to user input? - php

Can someone help me to figure out how to replace a defined string value with user input value? I am quite new in PHP programming and could not find an answer. I saw a lot of ways to replace string on the internet by using built-in functions or in arrays, but I could not find out the right answer to my question.
Here is my code:
$text = "Not found";
if ( isset($_GET['user'])) {
$user_input = $_GET['user'];
}
// from here I I tried to replace the value $text to user input, but it does not work.
$raw = TRUE;
$spec_char = "";
if ($raw) {
$raw = htmlentities($text);
echo "<p style='font-style:bold;'> PIN " . $raw . "</p>"; *# displays "Not found"*
} elseif (!$raw == TRUE ) {
$spec_char = htmlspecialchars($user_input);
echo "<p>PIN $spec_char </p>";
}
<form>
<input type="text" name="user" size="40" />
<input type="submit" value="User_val"/>
</form>
I appreciate your answers.

Lets run over your code, line by line.
// Set a default value for $text
$text = "Not found";
// Check if a value has been set...
if (isset($_GET['user'])) {
// But then create a new var with that value.
// Why? Are you going to change it?
$user_input = $_GET['user'];
}
// Define a few vars
$raw = TRUE;
$spec_char = "";
// This next line is useless - Why? Because $raw is always true.
// A better test would be to check for $user_input or do the
// isset() check here instead.
if ($raw) {
// Basic sanity check, but $text is always going to be
// "Not found" - as you have never changed it.
$raw = htmlentities($text);
// render some HTML - but as you said, always going to display
// "Not found"
echo "<p style='font-style:bold;'> PIN " . $raw . "</p>";
} elseif (!$raw == TRUE ) {
// This code is never reached.
$spec_char = htmlspecialchars($user_input);
echo "<p>PIN $spec_char </p>";
}
// I have no idea what this HTML is for really.
// Guessing this is your "input" values.
<form>
<input type="text" name="user" size="40" />
<input type="submit" value="User_val"/>
</form>
Just a guess I think you really wanted to do something more like this:
<?php
// Check if a value has been posted...
if (isset($_POST['user'])) {
// render some HTML
echo '<p style="font-style:bold"> PIN '.htmlspecialchars($_POST['user']).'</p>';
}
?>
<form method="post" action="?">
<input type="text" name="user" size="40" />
<input type="submit" value="User_val"/>
</form>

Related

else not executing in php

If I leave all the fields blank, the code blow is not showing the else message.
<form action="index.php" method="POST">
<textarea name="input_area" rows="6" cols="20"></textarea><br/><br/>
Search<input type="text" name="find"/><br/><br/>
Replace<input type="text" name="replace" /><br/><br/>
<input type="submit" value="Find and replace"/>
</form>
PHP
if(isset($_POST['input_area'])&&($_POST['find'])&&($_POST['replace']))
{
$text=$_POST['input_area'];
$find=$_POST['find'];
$replace=$_POST['replace'];
if(!empty($text)&&!empty($find)&&!empty($replace))
{
$new_str=str_replace($find,$replace,$text);
echo $new_str;
}
else
{
echo 'FILL ALL THE FIELDS';
}
}
The values will be set in $_POST, but they will be blank. A check like this would work in all situations, even in some cases where someone has modified your html and tried something funny.
<?php
$text = isset($_POST['input_area']) ? $_POST['input_area'] : "";
$find = isset($_POST['find']) ? $_POST['find'] : "";
$replace = isset($_POST['replace']) ? $_POST['find'] : "";
if($text != "" && $find != "" && $replace != ""){
$new_str=str_replace($find,$replace,$text);
echo $new_str;
}else{
echo 'FILL ALL THE FIELDS';
}
?>
This statement is the root of the problem
if(isset($_POST['input_area'])&&($_POST['find'])&&($_POST['replace']))
The correct one is
if(isset($_POST['input_area'])&&isset($_POST['find'])&&isset($_POST['replace']))
Aman has a pretty good answer. You may want to check if a user just entered spaces though. Look up ctype_space($str) for that. You could also adapt strlen for this purpose and trim to knock off whitespaces that may appear at the beginning or end of the input (or all of it)... if you want your code structure to look the same.
if ( strlen(trim($_POST['input_area']))>0 && etc.

Preserving two random numbers through game loop

My code should provide two random numbers and have the user enter their product (multiplication).
If you enter a wrong answer, it tells you to guess again, but keeps the same random numbers until you answer correctly. Answer correctly, and it starts over with a new pair of numbers.
The below code changes the value of the two random numbers even if I entered the wrong number. I would like to keep the values the same until the correct answer is entered.
<?php
$num1=rand(1, 9);
$num2=rand(1, 9);
$num3=$num1*$num2;
$num_to_guess = $num3;
echo $num1."x".$num2."= <br>";
if ($_POST['guess'] == $num_to_guess)
{ // matches!
$message = "Well done!";
}
elseif ($_POST['guess'] > $num_to_guess)
{
$message = $_POST['guess']." is too big! Try a smaller number.";
}
elseif ($_POST['guess'] < $num_to_guess)
{
$message = $_POST['guess']." is too small! Try a larger number.";
}
else
{ // some other condition
$message = "I am terribly confused.";
}
?>
<!DOCTYPE html>
<html>
<body>
<h2><?php echo $message; ?></h2>
<form method="POST" action="<?php echo $_SERVER['PHP_SELF']; ?>">
<input type="hidden" name="answer" value="<?php echo $answer;?>">
<input type="hidden" name="expression" value="<?php echo $expression;?>">
What is the value of the following multiplication expression: <br><br>
<?php echo $expression; ?> <input type="text" name="guess"><br>
<input type="submit" value="Check">
</form>
</body>
</html>
In order to keep the same numbers, you have to store them on the page and then check them when the form is submitted using php. You must also set the random number if the form was never submitted. In your case, you were always changing num1 and num2. I tried to leave as much of your original code intact, but it still needs some work to simplify it.
First I added 2 more hidden field in the html called num1 and num2
Second, I set $num1 and $num2 to the value that was submitted from the form.
After following the rest of the logic, I make sure that $num1 and $num2 are reset if the answer is correct of it the form was never submitted.
You can see the comments in the code below.
Additionally, if you were going to use this in a production environment, you would want to validate the values being passed in from the form so that malicious users don't take advantage of your code. :)
<?php
// Setting $num1 and $num2 to what was posted previously and performing the math on it.
$num1 = $_POST['num1'];
$num2 = $_POST['num2'];
$num_to_guess = $num1*$num2;
// Check for the correct answer
if ($_POST && $_POST['guess'] == $num_to_guess)
{
// matches!
$message = "Well done!";
$num1=rand(1, 9);
$num2=rand(1, 9);
}
// Give the user a hint that the number is too big
elseif ($_POST['guess'] > $num_to_guess)
{
$message = $_POST['guess']." is too big! Try a smaller number.";
}
// Give the user a hint that the number is too small
elseif ($_POST['guess'] < $num_to_guess)
{
$message = $_POST['guess']." is too small! Try a larger number.";
}
// If the form wasn't submitted i.e. no POST or something else went wrong
else
{
// Only display this message if the form was submitted, but there were no expected values
if ($_POST)
{
// some other condition and only if something was posted
$message = "I am terribly confused.";
}
// set num1 and num2 if there wasn't anything posted
$num1=rand(1, 9);
$num2=rand(1, 9);
}
// Show the problem
echo $num1."x".$num2."= <br>";
?>
<!DOCTYPE html>
<html>
<body>
<h2><?php echo $message; ?></h2>
<form method="POST" action="<?php echo $_SERVER['PHP_SELF']; ?>">
<input type="hidden" name="num1" value="<?= $num1 ?>" />
<input type="hidden" name="num2" value="<?= $num2 ?>" />
<input type="hidden" name="answer" value="<?php echo $num3;?>">
<input type="hidden" name="expression" value="<?php echo $expression;?>">
What is the value of the following multiplication expression: <br><br>
<input type="text" name="guess"><br>
<input type="submit" value="Check">
</form>
</body>
</html>
When you load the page for the first time, you have (i.e.) “2*3” as question. $_POST is not defined, so if ($_POST['guess']... will produce a undefined index warning. Then you echo $message, but where you define $message? $_POST['guess'] is undefined, so is evaluated as 0, $num_to_guess is 6 (=2*3), so $message is set to " is too small! Try a larger number.", even if the user has not input anything. The hidden answer is set to $answer, but this variable is not defined so it is set to nothing (or to “Notice: Undefined variable: answer”, if you activate error reporting). Same issue for expression input and for echo $expression.
Try something like this:
$newQuestion = True; // This variable to check if a new multiplication is required
$message = '';
/* $_POST['guess'] check only if form is submitted: */
if( isset( $_POST['guess'] ) )
{
/* Comparison with answer, not with new result: */
if( $_POST['guess'] == $_POST['answer'] )
{
$message = "Well done!";
}
else
{
/* If result if wrong, no new question needed, so we propose same question: */
$newQuestion = False;
$answer = $_POST['answer'];
$expression = $_POST['expression'];
if( $_POST['guess'] > $_POST['answer'] )
{
$message = "{$_POST['guess']} is too big! Try a smaller number.";
}
else
{
$message = "{$_POST['guess']} is too small! Try a larger number.";
}
}
}
/* New question is generated only on first page load or if previous answer is ok: */
if( $newQuestion )
{
$num1 = rand( 1, 9 );
$num2 = rand( 1, 9 );
$answer = $num1*$num2;
$expression = "$num1 x $num2";
if( $message ) $message .= "<br>Try a new one:";
else $message = "Try:";
}
?>
<!DOCTYPE html>
(... Your HTML Here ...)
This might also be fun to learn. This is a session. Lets you store something temporarily. It is a little dirty. But fun to learn from.
http://www.w3schools.com/php/php_sessions.asp
<?php
session_start(); // Starts the Session.
function Save() { // Function to save $num1 and $num2 in a Session.
$_SESSION['num1'] = rand(1, 9);
$_SESSION['num2'] = rand(1, 9);
$_SESSION['num_to_guess'] = $_SESSION['num1']*$_SESSION['num2'];;
$Som = 'Guess the number: ' . $_SESSION['num1'] .'*' .$_SESSION['num2'];
}
// If there is no session set
if (!isset($_SESSION['num_to_guess'])) {
Save();
$message = "";
}
if (isset($_POST['guess'])) {
// Check for the correct answer
if ($_POST['guess'] == $_SESSION['num_to_guess']) {
$message = "Well done!";
session_destroy(); // Destroys the Session.
Save(); // Set new Sessions.
}
// Give the user a hint that the number is too big
elseif ($_POST['guess'] > $_SESSION['num_to_guess']) {
$message = $_POST['guess']." is too big! Try a smaller number.";
$Som = 'Guess the number: ' . $_SESSION['num1'] .'*' .$_SESSION['num2'];
}
// Give the user a hint that the number is too small
elseif ($_POST['guess'] < $_SESSION['num_to_guess']) {
$message = $_POST['guess']." is too small! Try a larger number.";
$Som = 'Guess the number: ' . $_SESSION['num1'] .'*' .$_SESSION['num2'];
}
// some other condition
else {
$message = "I am terribly confused.";
}
}
?>
<html>
<body>
<h2><?php echo $Som . '<br>'; ?>
<?php echo $message; ?></h2>
<form method="POST" action="<?php echo $_SERVER['PHP_SELF']; ?>">
<input type="text" name="guess"><br>
<input type="submit" value="Check">
</form>
</body>
</html>

Passing information using post method without session variables

I will admit immediately that this is homework. I am only here as a last resort after I cannot find a suitable answer elsewhere. My assignment is having me pass information between posts without using a session variable or cookies in php. Essentially as the user continues to guess a hidden variable carries over all the past guesses up to that point. I am trying to build a string variable that holds them all and then assign it to the post variable but I cannot get anything to read off of the guessCounter variable i either get an undefined index error at the line of code that should be adding to my string variable or im just not getting anything passed over at all. here is my code any help would be greatly appreciated as I have been at this for awhile now.
<?php
if(isset($_POST['playerGuess'])) {
echo "<pre>"; print_r($_POST) ; echo "</pre>";
}
?>
<?php
$wordChoices = array("grape", "apple", "orange", "banana", "plum", "grapefruit");
$textToPlayer = "<font color = 'red'>It's time to play the guessing game!(1)</font>";
$theRightAnswer= array_rand($wordChoices, 1);
$passItOn = " ";
$_POST['guessCounter']=$passItOn;
$guessTestTracker = $_POST['guessCounter'];
$_POST['theAnswer'] = $theRightAnswer;
if(isset($_POST['playerGuess'])) {
$passItOn = $_POST['playerGuess'];
if ($_SERVER['REQUEST_METHOD'] == 'GET') {
$guessTestTracker = $_GET['guessCounter'];
$theRightAnswer = $_GET['theAnswer'];
}
else if ($_SERVER['REQUEST_METHOD'] == 'POST') {
if(isset($_POST['playerGuess'])) {
if(empty($_POST['playerGuess'])) {
$textToPlayer = "<font color = 'red'>Come on, enter something(2)</font>";
}
else if(in_array($_POST['playerGuess'],$wordChoices)==false) {
$textToPlayer = "<font color = 'red'>Hey, that's not even a valid guess. Try again (5)</font>";
$passItOn = $_POST['guessCounter'].$passItOn;
}
if(in_array($_POST['playerGuess'],$wordChoices)&&$_POST['playerGuess']!=$wordChoices[$theRightAnswer]) {
$textToPlayer = "<font color = 'red'>Sorry ".$_POST['playerGuess']." is wrong. Try again(4)</font>";
$passItOn = $_POST['guessCounter'].$passItOn;
}
if($_POST['playerGuess']==$wordChoices[$theRightAnswer]) {
$textToPlayer = "<font color = 'red'>You guessed ".$_POST['playerGuess']." and that's CORRECT!!!(3)</font>";
$passItOn = $_POST['guessCounter'].$passItOn;
}
}
}
}
$_POST['guessCounter'] = $passItOn;
$theRightAnswer=$_POST['theAnswer'];
for($i=0;$i<count($wordChoices);$i++){
if($i==$theRightAnswer) {
echo "<font color = 'green'>$wordChoices[$i]</font>";
}
else {
echo $wordChoices[$i];
}
if($i != count($wordChoices) - 1) {
echo " | ";
}
}
?>
<h1>Word Guess</h1>
Refresh this page
<h3>Guess the word I'm thinking</h3>
<form action ="<?php echo $_SERVER['PHP_SELF']; ?>" method = "post">
<input type = "text" name = "playerGuess" size = 20>
<input type = "hidden" name = "guessCounter" value = "<?php echo $guessTestTracker; ?>">
<input type = "hidden" name = "theAnswer" value = "<?php echo $theRightAnswer; ?>">
<input type = "submit" value="GUESS" name = "submitButton">
</form>
<?php
echo $textToPlayer;
echo $theRightAnswer;
echo $guessTestTracker;
?>
This is a minimal functional example of what you need to do. There are still a couple of minor bugs (like duplicate entries in the history), but I've left these as an exercise for you. Treat this as a starting point and build up what you need from it.
I've added comments to explain what's happening, so hopefully it is clear to you.
$answer = null;
$history = [];
$choices = ['apple', 'grape', 'banana'];
$message = '';
// check if a guess has been made.
if (!empty($_POST) && !empty($_POST['guess'])) {
// check if previous guesses have been made.
if (!empty($_POST['history'])) {
$history = explode(',', $_POST['history']);
}
// check guess.
if (!empty($_POST['answer']) && !empty($_POST['guess'])) {
// check guess and answer are both valid.
if (in_array($_POST['guess'], $choices) && isset($choices[$_POST['answer']])) {
if ($_POST['guess'] == $choices[$_POST['answer']]) {
// correct; clear history.
$history = [];
$message = 'correct!';
} else {
// incorrect; add to history and set previous answer to current.
$history[] = $_POST['guess'];
$answer = $_POST['answer'];
$message = 'incorrect!';
}
} else {
// invalid choice or answer value.
}
}
}
if (empty($answer)) {
// no answer set yet (new page load or correct guess); create new answer.
$answer = rand(0, count($choices) - 1);
}
?>
<p>Guess the word I'm thinking:</p>
<p><?php echo implode(' | ', $choices) ?></p>
<form method="POST">
<input type="hidden" name="answer" value="<?php echo $answer; ?>">
<input type="hidden" name="history" value="<?php echo implode(',', $history); ?>">
<input type="text" name="guess">
<input type="submit" name="submit" value="Guess">
</form>
<p><?php echo $message; ?></p>

select all checkboxes if none are select in php query

I have a script wher users can find exercise from a database, I have checkboxes for the user to find specific exercises the script works fine when a least 1 checkbox is selected from each checkbox group however I would like it that if no checkboxes was selected then it would the results of all checkboxes.
my checkbox form looks like this
<form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" name="criteria">
<p><strong>MUSCLE GROUP</strong></p>
<input type="checkbox" name="muscle[]" id="abdominals" value="abdominals"/>Abdominals<br />
<input type="checkbox" name="muscle[]" id="biceps" value="biceps" />Biceps<br />
<input type="checkbox" name="muscle[]" id="calves" value="calves" />Calves<br />
ect...
<br /><p><strong>EQUIPMENT (please select a least one)</strong></p>
<input type="checkbox" name="equipment[]" id="equipment" value="bands"/>Bands<br />
<input type="checkbox" name="equipment[]" id="equipment" value="barbell" />Barbell<br />
<input type="checkbox" name="equipment[]" id="equipment" value="dumbbell" />Dumbbell<br />
ect....
<input type="submit" name="sub" value="Generate Query" />
</form>
and here is my script
<?php
if(isset($_POST['muscle']) && !empty($_POST['muscle'])){
if(isset($_POST['equipment']) && !empty($_POST['equipment'])){
//get the function
include ($_SERVER['DOCUMENT_ROOT'] .'/scripts/functions.php');
$page = (int) (!isset($_GET["page"]) ? 1 : $_GET["page"]);
$limit = 14;
$startpoint = ($page * $limit) - $limit;
// Runs mysql_real_escape_string() on every value encountered.
$clean_muscle = array_map('mysql_real_escape_string', $_REQUEST['muscle']);
$clean_equipment = array_map('mysql_real_escape_string', $_REQUEST['equipment']);
// Convert the array into a string.
$muscle = implode("','", $clean_muscle);
$equipment = implode("','", $clean_equipment);
$options = array();
if(array($muscle))
{
$options[] = "muscle IN ('$muscle')";
}
if(array($equipment))
{
$options[] = "equipment IN ('$equipment')";
}
$fullsearch = implode(' AND ', $options);
$statement = "mytable";
if ($fullsearch <> '') {
$statement .= " WHERE " . $fullsearch;
}
if(!$query=mysql_query("SELECT * FROM {$statement} LIMIT {$startpoint} , {$limit}"))
{
echo "Cannot parse query";
}
elseif(mysql_num_rows($query) == 0) {
echo "No records found";
}
else {
echo "";
while($row = mysql_fetch_assoc($query)) {
echo "".$row['name'] ."</br>
".$row['description'] ."";
}
}
echo "<div class=\"new-pagination\">";
echo pagination($statement,$limit,$page);
echo "</div>";
}
}
Im new with php so my code may not be the best. If anyone can help me or point me in the right direction I would be very greatful.
OK - I think I have figured it all out. You were right - the main problem was in your isset and isempty calls. I created some variations on your file, and this shows what is going on. Note - since I don't have some of your "other" functions, I am only showing what is going wrong in the outer parts of your function.
Part 1: validating function
In the following code, I have added two JavaScript functions to the input form; these were loosely based on scripts you can find when you google "JavaScript validation checkbox". The oneBoxSet(groupName) function will look through all document elements; find the ones of type checkBox, see if one of them is checked, and if so, confirms that it belongs to groupName. For now, it returns "true" or "false". The calling function, validateMe(formName), runs your validation. It is called by adding
onclick="validateMe('criteria'); return false;"
to the code of the submit button. This basically says "call this function with this parameter to validate the form". In this case the function "fixes" the data and submits; but you could imagine that it returns "false", in which case the submit action will be canceled.
In the validateMe function we check whether at least one box is checked in each group; if it is not, then a hidden box in the "all[]" group is set accordingly.
I changed the code a little bit - it calls a different script (muscle.php) instead of the <?php echo $_SERVER['PHP_SELF']; ?> you had... obviously the principle is the same.
After this initial code we will look at some stuff I added in muscle.php to confirm what your original problem was.
<html>
<head>
<script type="text/javascript">
// go through all checkboxes; see if at least one with name 'groupName' is set
// if so, return true; otherwise return false
function oneBoxSet(groupName)
{
var c=document.getElementsByTagName('input');
for (var i = 0; i<c.length; i++){
if (c[i].type=='checkbox')
{
if (c[i].checked) {
if (c[i].name == groupName) {
return true; // at least one box in this group is checked
}
}
}
}
return false; // never found a good checkbox
}
function setAllBoxes(groupName, TF)
{
// set the 'checked' property of all inputs in this group to 'TF' (true or false)
var c=document.getElementsByTagName('input');
// alert("setting all boxes for " + groupName + " to " + TF);
for (var i = 0; i<c.length; i++){
if (c[i].type=='checkbox')
{
if (c[i].name == groupName) {
c[i].checked = TF;
}
}
}
return 0;
}
// this function is run when submit is pressed:
function validateMe(formName) {
if (oneBoxSet('muscle[]')) {
document.getElementById("allMuscles").value = "selectedMuscles";
//alert("muscle OK!");
}
else {
document.getElementById("allMuscles").value = "allMuscles";
// and/or insert code that sets all boxes in this group:
setAllBoxes('muscle[]', true);
alert("No muscle group was selected - has been set to ALL");
}
if (oneBoxSet('equipment[]')) {
document.getElementById("allEquipment").value = "selectedEquipment";
//alert("equipment OK!");
}
else {
document.getElementById("allEquipment").value = "allEquipment";
// instead, you could insert code here that sets all boxes in this category to true
setAllBoxes('equipment[]', true);
alert("No equipment was selected - has been set to ALL");
}
// submit the form - function never returns
document.forms[formName].submit();
}
</script>
</head>
<body>
<form action="muscle.php" method="post" name="criteria">
<p><strong>MUSCLE GROUP</strong></p>
<input type="checkbox" name="muscle[]" id="abdominals" value="abdominals"/>Abdominals<br />
<input type="checkbox" name="muscle[]" id="biceps" value="biceps" />Biceps<br />
<input type="checkbox" name="muscle[]" id="calves" value="calves" />Calves<br />
<input type="hidden" name="all[]" id="allMuscles" value="selectedMuscles" />
etc...<br>
<br /><p><strong>EQUIPMENT (please select a least one)</strong></p>
<input type="checkbox" name="equipment[]" id="equipment" value="bands"/>Bands<br />
<input type="checkbox" name="equipment[]" id="equipment" value="barbell" />Barbell<br />
<input type="checkbox" name="equipment[]" id="equipment" value="dumbbell" />Dumbbell<br />
<input type="hidden" name="all[]" id="allEquipment" value="selectedEquipment" />
<br>
<input type="submit" name="sub" value="Generate Query" onclick="validateMe('criteria'); return false;" />
</form>
</body>
</html>
Part 2: what's wrong with the PHP?
Now here is a new start to the php script. It checks the conditions that you were testing at the start of your original script, and demonstrates that you never get past the initial if statements if a check box wasn't set in one of the groups. I suggest that you leave these tests out altogether, and instead get inspiration from the code I wrote to fix any issues. For example, you can test whether equipmentAll or muscleAll were set, and create the appropriate query string accordingly.
<?php
echo 'file was called successfully<br><br>';
if(isset($_POST['muscle'])) {
echo "_POST[muscle] is set<br>";
print_r($_POST[muscle]);
echo "<br>";
if (!empty($_POST['muscle'])) {
echo "_POST[muscle] is not empty!<br>";
}
else {
echo "_POST[muscle] is empty!<br>";
}
}
else {
echo "_POST[muscle] is not set: it is empty!<br>";
}
if(isset($_POST['equipment'])) {
echo "_POST[equipment] is set<br>";
print_r($_POST['equipment']);
echo "<br>";
if (!empty($_POST['equipment'])) {
echo "_POST[equipment] is not empty!<br>";
}
else {
echo "_POST[equipment] is empty!<br>";
}
}
else {
echo "_POST[equipment] is not set: it is empty!<br>";
}
if(isset($_POST['all'])) {
echo "this is what you have to do:<br>";
print_r($_POST['all']);
echo "<br>";
}
// if(isset($_POST['muscle']) && !empty($_POST['muscle'])){
// if(isset($_POST['equipment']) && !empty($_POST['equipment'])){
If you call this with no check boxes selected, you get two dialogs ('not OK!'), then the following output:
file was called successfully
_POST[muscle] is not set: it is empty!
_POST[equipment] is not set: it is empty!
this is what you have to do:
Array ( [0] => allMuscles [1] => allEquipment )
If you select a couple of boxes in the first group, and none in the second:
file was called successfully
_POST[muscle] is set
Array ( [0] => abdominals [1] => calves )
_POST[muscle] is not empty!
_POST[equipment] is not set: it is empty!
this is what you have to do:
Array ( [0] => selectedMuscles [1] => allEquipment )
I do not claim to write beautiful code; but I hope this is functional, and gets you out of the fix you were in. Good luck!

Why is that !isset does not seem to work?

I am new to the world of PHP and have put together a form that multiplies an entered value. However when I attempt to validate if a person has not entered any values to return an error message, it does display the message. My code below. Appreciate if you could also suggest improvements.
<?php
$counter = 0;
if(isset($_POST["submit"])) {
$start = $_POST["start"];
$end = $_POST["end"];
$multiply = $_POST["multiplication"];
// if($_POST["start"] == "" && $_POST["end"] == "" && $_POST["multiplication"] == "") {
// print "Please enter some values";
// }
if(!isset($_POST["start"], $_POST["end"], $_POST["multiplication"])) {
print "Please enter some values";
}
// for($start;$start<$end;$start++) {
// $counter = $counter +1;
// $multiplication = $counter * $multiply;
// print "$counter <br />";
// print "$counter multiplied by $multiply = $multiplication <br />";
// }
}
?>
<html>
<head>
<title>Sample Multiplication</title>
</head>
<body>
<form name="multiply" method="post" action="multiplication_sample.php">
<input type="text" name="start" value="<?php if(isset($_POST["start"])) { print $start; } ?>">
<input type="text" name="end" value="<?php if(isset($_POST["end"])) { print $end; } ?>">
<input type="text" name="multiplication" value="<?php if(isset($_POST["multiplication"])) { print $multiply; } ?>">
<input type="submit" name="submit" value="submit">
</form>
<?php
if(isset($_POST["submit"])) {
for($start;$start<$end;$start++) {
$counter = $counter + 1;
$multiplication = $counter * $multiply;
print "$counter multiplied by $multiply = $multiplication <br />";
}
}
?>
</body>
</html>
I think that isset will make sure a variable is not NULL, however, "blank" is not the same as null. If you submit a form with blank values, the variable is still being set, it is just empty.
When the form is submitted, the content of the input fields is sent to the server.
If those input fields are empty, the server gets an empty string for each input -- but it gets something ; so, the $_POST["start"], $_POST["end"], $_POST["multiplication"] items are set -- even if they only contain empty strings.
You could check :
If the fields contain an empty string : if ($_POST["start"] === '')
Or if if contains only blank spaces : if (trim($_POST["start"]) === '')
Or if they are empty : if (empty($_POST["start"]))
If the fields aren't defined your code will print your message in the html before the <html> tag appears. Most browsers won't display it or display it in an unexpected place.
You should move the message display somewhere in the html where the user could see it.
And as other pointed out, except on the first call of the page the fields will have an empty value but still exists (and so isset will return TRUE)
I hope, I understand you right. It is
if(!isset($_POST["start"], $_POST["end"], $_POST["multiplication"])) {
print "Please enter some values";
}
that works not as expected? It seems, that you assume an empty string means, that nothing is set, what is not true.
$x = "";
isset($x); // true
Use empty() or just $_POST['start'] == '' instead.

Categories