jQuery on Twig Template [duplicate]

Question

I am trying to create a basic jQuery function on my twig template but I can't seem to get it to work. Can someone please help me!?

My Twig File is as follows:

{% block javascripts %}
    {#if you include jquery here, the scripts that need jquery will fail because jquery exists since this point !#}

    <script type="text/javascript" src="{{ asset('js/jquery.min.js') }}">
    $(".nav li.expanded").hover(
        function(){
          $(this).addClass("open");
        },function(){
          $(this).removeClass("open");
        }
      alert("Inside Function");
      );
      alert("Outside Function");
      $(document).ready(function(){
        alert("Ready!");
      });
    </script>
{% endblock %}
{% set heading_id = attributes.id ~ '-menu'|clean_id %}
<nav role="navigation" aria-labelledby="{{ heading_id }}"{{ attributes.removeClass('clearfix')|without('role', 'aria-labelledby') }}>
  {# Label. If not displayed, we still provide it for screen readers. #}
  {% if not configuration.label_display %}
    {% set title_attributes = title_attributes.addClass('sr-only') %}
  {% endif %}
  <h2{{ title_attributes.setAttribute('id', heading_id) }}>{{ configuration.label }}</h2>

  {% block content %}
    {{ content }}
  {% endblock %}

Error Output:

The website encountered an unexpected error. Please try again later.</br></br><em class="placeholder">Twig_Error_Syntax</em>: Unknown &quot;asset&quot; function. in <em class="placeholder">Twig_ExpressionParser-&gt;getFunctionNodeClass()</em> (line <em class="placeholder">38</em> of <em class="placeholder">themes/custom/navy/templates/block/block--system-menu-block--main.html.twig</em>). <pre class="backtrace">Twig_ExpressionParser-&gt;getFunctionNode(&#039;asset&#039;, 38) (Line: 162)
Twig_ExpressionParser-&gt;parsePrimaryExpression() (Line: 102)
Twig_ExpressionParser-&gt;getPrimary() (Line: 55)
Twig_ExpressionParser-&gt;parseExpression() (Line: 149)
Twig_Parser-&gt;subparse(Array, 1) (Line: 40)
Twig_TokenParser_Block-&gt;parse(Object) (Line: 192)
Twig_Parser-&gt;subparse(NULL, ) (Line: 105)
Twig_Parser-&gt;parse(Object) (Line: 716)
Twig_Environment-&gt;parse(Object) (Line: 774)
Twig_Environment-&gt;compileSource(Object) (Line: 452)
Twig_Environment-&gt;loadTemplate(&#039;themes/custom/navy/templates/block/block--system-menu-block--main.html.twig&#039;) (Line: 64)
twig_render_template(&#039;themes/custom/navy/templates/block/block--system-menu-block--main.html.twig&#039;, Array) (Line: 384)
Drupal\Core\Theme\ThemeManager-&gt;render(&#039;block&#039;, Array) (Line: 437)
Drupal\Core\Render\Renderer-&gt;doRender(Array) (Line: 450)
Drupal\Core\Render\Renderer-&gt;doRender(Array, ) (Line: 195)
Drupal\Core\Render\Renderer-&gt;render(Array) (Line: 490)
Drupal\Core\Template\TwigExtension-&gt;escapeFilter(Object, Array, &#039;html&#039;, NULL, 1) (Line: 182)
__TwigTemplate_7206b6943ab6709e209af4c71d787052441f5e0fc6966fa51bfb08236a79f5ef-&gt;block_main(Array, Array) (Line: 215)
Twig_Template-&gt;displayBlock(&#039;main&#039;, Array, Array) (Line: 65)
__TwigTemplate_7206b6943ab6709e209af4c71d787052441f5e0fc6966fa51bfb08236a79f5ef-&gt;doDisplay(Array, Array) (Line: 432)
Twig_Template-&gt;displayWithErrorHandling(Array, Array) (Line: 403)
Twig_Template-&gt;display(Array) (Line: 411)
Twig_Template-&gt;render(Array) (Line: 64)
twig_render_template(&#039;themes/custom/navy/templates/page/page.html.twig&#039;, Array) (Line: 384)
Drupal\Core\Theme\ThemeManager-&gt;render(&#039;page&#039;, Array) (Line: 437)
Drupal\Core\Render\Renderer-&gt;doRender(Array, ) (Line: 195)
Drupal\Core\Render\Renderer-&gt;render(Array) (Line: 490)
Drupal\Core\Template\TwigExtension-&gt;escapeFilter(Object, Array, &#039;html&#039;, NULL, 1) (Line: 90)
__TwigTemplate_1851d7a76e53df9c9a6b9fa5328c4c7d784772b2109ead0be693668c41ae4e88-&gt;doDisplay(Array, Array) (Line: 432)
Twig_Template-&gt;displayWithErrorHandling(Array, Array) (Line: 403)
Twig_Template-&gt;display(Array) (Line: 411)
Twig_Template-&gt;render(Array) (Line: 64)
twig_render_template(&#039;themes/contrib/bootstrap/templates/system/html.html.twig&#039;, Array) (Line: 384)
Drupal\Core\Theme\ThemeManager-&gt;render(&#039;html&#039;, Array) (Line: 437)
Drupal\Core\Render\Renderer-&gt;doRender(Array, ) (Line: 195)
Drupal\Core\Render\Renderer-&gt;render(Array) (Line: 147)
Drupal\Core\Render\MainContent\HtmlRenderer-&gt;Drupal\Core\Render\MainContent\{closure}() (Line: 582)
Drupal\Core\Render\Renderer-&gt;executeInRenderContext(Object, Object) (Line: 148)
Drupal\Core\Render\MainContent\HtmlRenderer-&gt;renderResponse(Array, Object, Object) (Line: 90)
Drupal\Core\EventSubscriber\MainContentViewSubscriber-&gt;onViewRenderArray(Object, &#039;kernel.view&#039;, Object)
call_user_func(Array, Object, &#039;kernel.view&#039;, Object) (Line: 111)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher-&gt;dispatch(&#039;kernel.view&#039;, Object) (Line: 156)
Symfony\Component\HttpKernel\HttpKernel-&gt;handleRaw(Object, 1) (Line: 68)
Symfony\Component\HttpKernel\HttpKernel-&gt;handle(Object, 1, 1) (Line: 67)
Drupal\simple_oauth\HttpMiddleware\BasicAuthSwap-&gt;handle(Object, 1, 1) (Line: 57)
Drupal\Core\StackMiddleware\Session-&gt;handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\KernelPreHandle-&gt;handle(Object, 1, 1) (Line: 99)
Drupal\page_cache\StackMiddleware\PageCache-&gt;pass(Object, 1, 1) (Line: 78)
Drupal\page_cache\StackMiddleware\PageCache-&gt;handle(Object, 1, 1) (Line: 40)
Drupal\jsonapi\StackMiddleware\FormatSetter-&gt;handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware-&gt;handle(Object, 1, 1) (Line: 52)
Drupal\Core\StackMiddleware\NegotiationMiddleware-&gt;handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel-&gt;handle(Object, 1, 1) (Line: 666)
Drupal\Core\DrupalKernel-&gt;handle(Object) (Line: 19)
</pre>

Answer 1

There are a few things going wrong:

1. jQuery is in no conflict mode, so there's no global $. A common pattern to provide it in the manner you're accustomed is:

   (function($) {
     $(...);
   })(jQuery);
   

2. Assuming you use a sensible theme, jQuery isn't actually available at that point in the document. The <script> tags are before the </body> tag.

3. You're not looking at your browser console, which would have told you much of this ;)

To include JS in a template, you should create a library, and attach it either in a preprocess function, or directly in the template itself with:

attach_library('mytheme/library')