Dec 3, 2008
Counting Characters php vs javascript
On a recent project, an issue cropped up where we were exporting xml reports to a third party, who had rules about line lengths in Description fields.
So, I wrote up a quick-and-dirty character counter for the description field so the client can keep their descriptions under the 1500-word limit.
Here’s how it was done:
if (!$fdata['description']) {
$errors[] = "You must enter a Description";
} elseif(strlen($fdata['description']) > 1500) {
$len = strlen($fdata['description']);
$errors[] = "Descriptions are limited to 1500 characters ($len)";
}
Now the html and javascript:
<li class="description">
<label for="htmlarea" class="required">Description *</label>
<textarea name="description" id="htmlarea" cols="80" rows="20" class="textarea">< ?= $ff['description'] ?></textarea>
<p class="hint" id="desc_char_count">1500 character limit</p>
</li>
$(function(){
$('#htmlarea').keyup(function(){
var charLength = $(this).val().length;
$('#desc_char_count').html(charLength + ' of 1500 characters used');
if($(this).val().length > 1500) {
$('#desc_char_count').removeClass('positive').addClass('negative').html('<strong>You have ' + $(this).val().length + ' characters. You may only have up to 1500 characters.</strong>');
} else {
$('#desc_char_count').addClass('positive').removeClass('negative');
}
});
$('#htmlarea').keyup();
});
All was working well, except I underestimated the descriptions. The next morning, the thing was broken. The php side was kicking validation errors (“over 1500 characters”), while the javascript was counting a mere 1480. Why?
Turns out the data was full of bullets and other multibyte characters. To make the counts match, I needed multibyte-safe php:
if (!$fdata['description']) {
$errors[] = "You must enter a Description";
} elseif(mb_strlen($fdata['description'],'UTF-8') > 1500) {
$len = mb_strlen($fdata['description'],'UTF-8');
$errors[] = "Descriptions are limited to 1500 characters ($len)";
}
Hooray! Now the counts match!
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