This error message indicates that the HTML code you are trying to process is too large for the PCRE (Perl Compatible Regular Expressions) library to handle. The backtrack limit is the maximum number of steps that PCRE will take to match a pattern, and it is set to 1000000 by default.
To resolve this issue, you can increase the backtrack limit in your PHP code. You can do this by setting the "pcre.backtrack_limit" directive in your PHP configuration file (php.ini) or by using the ini_set() function in your PHP code.
Here's an example of how to increase the backtrack limit using the ini_set() function:
ini_set('pcre.backtrack_limit', '10000000'); // Set the limit to 10 million
In this example, we set the backtrack limit to 10 million, which should be sufficient for most HTML documents. However, you may need to adjust this value depending on the size and complexity of your HTML code.
It's important to note that increasing the backtrack limit can have performance implications, as PCRE will need to take more steps to match patterns. Therefore, it's generally recommended to split large HTML documents into smaller chunks and process them separately to avoid hitting the backtrack limit altogether.