Truncate Text Within Specific HTML Tag - php

Question

This might not even be possible but I have quite a limited knowledge of PHP so I can't figure out if it is or not.
Basically I have a string $myText and this string outputs HTML in the following format:
<p>This is the main bit of text</p>
<small> This is some additional text</small>
My aim is to limit the number of characters displayed specifically within the <p> tag, for example 10 characters.
I have been playing around with PHP substr but I can only get this to work on all of the text, not just the text in the <p> tag.
Do you know if this is possible and if it is, do you know how to do it? Any pointers at all would be appreciated.
Thank you

Answer 1

The simplest solution is:
<?php
$text = '
<p>This is the main bit of text</p>
<small> This is some additional text</small>';
$pos = strpos($text,'<p>');
$pos2 = strpos($text,'</p>');
$text = '<p>' . substr($text,$pos+strlen('<p>'),10).substr($text,$pos2);
echo $text;
but it will work just for first pair of <p> ... </p>
If you need more, you can use regular expressions:
<?php
$text = '
<p>This is the main bit of text</p>
<small> This is some additional text</small>
<p>
werwerwrewre
</p>';
preg_match_all('#<p>(.*)</p>#isU', $text, $matches);
foreach ($matches[1] as $match) {
$text = str_replace('<p>'.$match.'</p>', '<p>'.substr($match,0,10).'</p>', $text);
}
echo $text;
or even
<?php
$text = '
<p>This is the main bit of text</p>
<small> This is some additional text</small>
<p>
werwerwrewre
</p>';
$text = preg_replace_callback('#<p>(.*)</p>#isU', function($matches) {
$matches[1] = '<p>'.substr($matches[1],0,10).'</p>';
return $matches[1];
}, $text);
echo $text;
However in those all 3 cases, all white characters are assumed as part of the string, so if the content of <p>...</p> starts with 3 spaces and you want to display only 3 characters, you simple display only 3 spaces, nothing more. Of course it can be quite easily modified, but I mentioned it to notice that fact.
And one more thing, quite possible you will need to use multibyte version of functions to get the result, so for example instead of strpos() you should use mb_strpos() and set earlier utf-8 encoding using mb_internal_encoding('UTF-8'); to make it working

Answer 2

You can achieve it by a quite simple way:
<?php
$max_length = 5;
$input = "<b>example: </b><div align=left>this is a test</div><div>another very very long item</div>";
$elements_count = preg_match_all("|(<[^>]+>)(.*)(</[^>]+>)|U",
$input,
$out, PREG_PATTERN_ORDER);
for($i=0; $i<$elements_count; $i++){
echo $out[1][$i].substr($out[2][$i], 0, $max_length).$out[3][$i]."\n";
}
these will work for any tag and any class or attribute within it.
ex. input:
<b>example: </b><div align=left>this is a test</div><div>another very very long item</div>
output:
<b>examp</b>
<div align=left>this </div>
<div>anoth</div>