- str_replace: documentation ( source)
<?php
$valid_strings = array("<p>"," ","</p>");
$test1 = "<p>asdasdasdasdasdasdasd</p>";
$test2 = "<p> </p>";
echo ContainsAnythingElseThan($test1,$valid_strings);
echo ContainsAnythingElseThan($test2,$valid_strings);
function ContainsAnythingElseThan($the_string,$the_valid_strings_array)
{
echo str_len(str_replace($the_valid_strings_array,"",$the_string));
}