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javahtmlspringthymeleaf

Dynamically adding attributes using Thymeleaf th:attr and th:attrappend

I want to add selected to HTML tag option using Thymeleaf dynamically by checking the condition of RequestParam:

<option value="en" th:text="${#httpServletRequest.getParameter('lang') == null || #httpServletRequest.getParameter('lang') == 'en'} ? #{lang.eng}"></option>
                        <option value="ru"  th:text="#{lang.ru}" th:attr="${#httpServletRequest.getParameter('lang') == 'ru'} ? 'selected' : null"></option>

But I have an error on the second option.

The reason for doing it because when I switch to another language the selected lang doesn't changing How I can solve this problem? Or I have to use another approach?

Solution

  • With selected attribute you should refer to Fixed value boolean attributes.

    That means instead of

    th:attr="${#httpServletRequest.getParameter('lang') == 'ru'} ? 'selected' : null"

    you can do:

    th:selected="${#httpServletRequest.getParameter('lang') == 'ru'}"