Editing Troubleshooting of selenium errors

[https://www.selenium.dev/ SeleniumHQ Browser Automation] ([https://github.com/php-webdriver/php-webdriver php-webdriver/php-webdriver: PHP client for Selenium/WebDriver protocol. Previously facebook/php-webdriver])

== How to tracking the selenium errors ==

* Checking the standalone selenium server is running or not {{kbd | key=<nowiki>ps aux | grep selenium</nowiki>}} on {{Linux}}
* Checking the log file of standalone selenium server e.g. launching the server by the command {{kbd | key=<nowiki>sudo nohup java -jar selenium-server-standalone-3.141.59.jar > /home/user/selenium.log 2>&1 &</nowiki>}}. The log file was located at {{kbd | key=<nowiki>/home/user/selenium.log</nowiki>}}
* (optional) Checking the port where the selenium server is running e.g. {{kbd | key=<nowiki>wget http://localhost:4444</nowiki>}}
* Checking the error log file of HTTP server e.g. {{kbd | key=<nowiki>sudo tail /var/log/nginx/error.log</nowiki>}}
* (optional) Checking the error log file of PHP-FPM defined in the configuration file {{kbd | key=<nowiki>/etc/php-fpm.d/www.conf</nowiki>}}

== 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>.

== How to resolve [WARNING]: This version of ChromeDriver only supports Chrome version xx or [WARNING]: This version of ChromeDriver has not been tested with Chrome version 86 ==

Situation
* [https://chromedriver.chromium.org/downloads Download] the same version of ChromeDriver with the version installed on the computer or server
* You may need to stop the ChromeDriver in the process list if you could not overwrite the existing ChromeDriver file
** {{Win}} (1) Open the command prompt with the administrative permission (2) and keyin {{kbd | key=<nowiki>taskkill /IM "chromedriver.exe" /F</nowiki>}} to stop the ChromeDriver process
** {{Linux}} 
* Overwrite the existing ChromeDriver file

== References ==
<references />

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