In PHP, why does </script> not show a parse error?
This must be because there are various ways of starting a block of PHP code:
<? ... ?>(known asshort_open_tag)<?php ... ?>(the standard really)<script language="php"> ... </script>(not recommended)<% ... %>(deprecated and removed ASP-style tag after 5.3.0)
Apparently, you can open a PHP block one way, and close it the other. Didn't know that.
So in your code, you opened the block using <? but PHP recognizes </script> as the closer. What happened was:
<?php <----- START PHP</script> <----- END PHP?> <----- JUST GARBAGE IN THE HTML
In PHP, you can use the script tag to open a PHP block.
So you can use
<script language="php"> echo 'hello world';</script>So in your example you have mixed the normal open tag, <?php, with the closing tag, </script>. So the parser assumes that all the text after the closing script tag is normal HTML.
Read more in Escaping from HTML.