Editing Troubleshooting of selenium errors (section)

== How to resolve Uncaught Facebook\WebDriver\Exception\InvalidSelectorException ==
Error message
<pre>
PHP Fatal error:  Uncaught Facebook\WebDriver\Exception\InvalidSelectorException: invalid selector: The result of the xpath expression "xxx" is: [object Attr]. It should be an element.
  (Session info: chrome=83.0.4103.61) in /path/to/vendor/php-webdriver/webdriver/lib/Exception/WebDriverException.php:105
</pre>

Situation
* After the term was keyed in into the text box, the script shuld auto click the specified button which specified by [https://www.w3schools.com/xml/xpath_syntax.asp XPath expression].

Possibile soultions
* Solution1: Using headless chrome<ref>[https://developers.google.com/web/updates/2017/04/headless-chrome Getting Started with Headless Chrome  |  Web  |  Google Developers]</ref>
* Solution2: Not click the button which specified by XPath expression. Send the {{kbd | key=ENTER}} to submit the form<ref>[https://stackoverflow.com/questions/21243860/emulate-keypress-in-webdriver-using-php selenium - Emulate keypress in webdriver using php - Stack Overflow]</ref>.