JSFiddle - React, Tailwind, and code Playground

HTML

<select>
    <option selected>
        
    </option>
</select>
Length of selected option value: <span id="result"></span>

JavaScript

var
 $r = $('#result'),
 $o = $('select option:selected'),
 result = '';

result += $o.val().length; 

// option changed: https://github.com/jquery/jquery/commit/92cbf5362cfe4fe52e919eecfebe8ecbe27ee5e3

// Try jquery.text
try{
  result += '.  jQuery.text of element returns length: ' + jQuery.text( $o[0]).length.toString() + '.  ';    
}catch(ex){ 
  result += '.  jQuery.text failed.  ';
}

// Try element.text
try{
  result += 'element.text returns length: ' + $o[0].text.length.toString() + '.';    
}catch(ex){
  result += '.  element.text failed.';
}


$r.text( result );