PHP Keyword Density Checker Fixes

It looks like you have a PHP class for checking keyword density on a webpage using cURL and text extraction. However, there are some issues in the code:

### Observations:
1. **Deprecated `var` Usage**
– The class is using `var $domain;` which is outdated. Use `public`, `protected`, or `private` instead.

2. **Improper Object Creation (`& new html2text`)**
– `$extraction =& new html2text($str, true);` should be replaced with `$extraction = new html2text($str, true);`. The `&` is unnecessary.

3. **Missing External Library (`html2text`)**
– The script requires `ext/class.html2text.inc`, which might not be available.

4. **Keyword Filtering Logic**
– The function `keywords_extract()` is filtering words, but there are redundancies between `$commonWords` and `$filterwordsArray`.

5. **Broken `calcDensity()`**
– It calls `keywordSorting()`, which is not defined in the code provided.
– `$this->ignore_word` is referenced but never declared.

### Suggested Fixes:
– Update `var $domain;` → `private $domain;`
– Remove `&` from `new html2text()`
– Ensure `class.html2text.inc` is available or use `strip_tags()` instead.
– Define the missing `keywordSorting()` function.

Would you like me to refine and optimize the script for modern PHP versions? 🚀