HTML Form Number Type Unique User Input with Javascript and PHP
Question
This question is a follow up to what I previously asked ( HTML Form Number Type Unique User Input ) but now I'm making the form more dynamic.
The following form asks users to list there 3 favorite genres of music:
<form id="genre" name="genre" method="post" action="musicsell.php">
<input type="checkbox" name="genre[]" id="Rap" value="Rap"/>Rap<br />
<input type="checkbox" name="genre[]" id="HipHop" value="HipHop"/>HipHop<br />
<input type="checkbox" name="genre[]" id="RnB" value="RnB"/>RnB<br />
<input type="checkbox" name="genre[]" id="Rock" value="Rock"/>Rock<br />
<input type="checkbox" name="genre[]" id="Jazz"value="Jazz"/>Jazz<br />
<p>
<input type="submit" value="Next">
<br />
</p>
</form>
From there, I am using the following code to make sure that they only use numbers 1,2, and 3 and a foreach loop to list what they have checked but how can I make sure they do not use the same number twice?
<body>
The genre(s) you selected are: <br />
<form id="form1" name="form1" method="post" action="musicresults.php">
<?php
$name = $_POST['genre'];
if(isset($_POST['genre'])) {
foreach ($name as $genre) {
?>
<input type="number" required="required" id="<?php echo $genre ?>" name="music[<?php echo $genre ?>]" max="3" min="1" />
<?php echo $genre ?>
<br />
<?php
}
}
?>
<input type="submit" name="button" id="button" value="Submit" />
</form>
</body>
This was the old javascript code from the previous question but now the id="" is generated by PHP above:
<script type="text/javascript">
function item() {
cake = Number(document.getElementById('cake').value);
twizlers = Number(document.getElementById('twizlers').value);
taffy = Number(document.getElementById('taffy').value);
if (cake == twizlers) {
alert("Some alert cake or twizlers");
return false;
} else if (twizlers == taffy) {
alert("Some alert taffy or twizlers");
return false;
} else if (taffy == cake) {
alert("Some alert taffy or cake");
return false;
} else {
return true;
}
}
</script>
How can this be done now? Does it have to be in a foreach loop? Any suggestions will be appreciated.
1 answers
solution1
0 2015-08-10 21:07:05
Unless they hack the form or build their own POST submission, they can't "use" the same checkbox twice. But you can easily check for duplicate values:
$counts = array_count_values(array_values($_POST['genre']));
foreach($counts as $form_value => $cnt) {
if ($cnt > 1) {
echo "$form_value was entered more than once";
}
}
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