code: public function selectForm($selected = null, $placeholder = null, array $selectAttributes = [], array $optionAttributes = [] )
  	{
  		$selectAttributesString = '';
  		foreach ($selectAttributes as $key => $value)
  		{
  			$selectAttributesString = $selectAttributesString . " " . $key . "='" . $value ."'";
  		}
  
  		$optionAttributesString = '';
  		foreach ($optionAttributes as $key => $value)
  		{
  			$optionAttributesString = $optionAttributesString . " " . $key . "='" . $value ."'";
  		}
  
  		$string = "<select". $selectAttributesString .">\n";
  
  		if (isset($placeholder) && (empty($selected)))
  		{
  		     $placeholder = "<option value='' disabled selected>{$placeholder}</option>";
  		}
  		else
  		{
  		      $placeholder = null;
  		}
  
  		$string = $string . $placeholder;
  		foreach ($this->timezoneList as $key => $value)
  		{
  			if ($selected == $value) {
  				$selectedString = "selected='" . $value . "'";
  			} else {
  				$selectedString = '';
  			}
  
  			$string = $string . "<option value='" . $value . "'" . $optionAttributesString . " " . $selectedString . ">" . $key . "</option>\n";
  		}
  		$string = $string . "</select>";
  
  		return $string;
  	}
docs: @param null $selected
  @param null $placeholder
  @param array $selectAttributes
  @param array $optionAttributes
  
  @return string