Jquery 如何在未在列表中指定事件的情况下触发 function

Question

I have a list of items and can be removed by clicking.

I need the first item to be the highlight only when there is one item on the list. I have tried to do that by the click event. However, would it be possible to do it without.click()? (or any other events). The reason is that this list is dynamically interacting with other lists that the list item may change by other functions.

In other words, the list is dynamically changing, could jquery keep checking whether there is only one item on the list (without specifying specific event trigger)?

<ul id="container">
<li>1</li>
<li class="fixed">2</li>
<li>3</li>
<li class="fixed">4</li>
<li>5</li>
</ul>

$('#container').delegate('li', 'click', function() {
  $(this).remove();
});


$('#container').click(function(){
  if ($('#container').children().length == 1) {
    $("#container li:first-child" ).css( "background-color", "#fff2ac" );
  }
}

Answer 1

You can do this purely with CSS with a rule that checks if the li is both the :first-child AND the :last-child -

 .container li:first-child:last-child { background-color: red; }

 <h5>List With Many Items</h5> <ul class="container"> <li>1</li> <li class="fixed">2</li> <li>3</li> <li class="fixed">4</li> <li>5</li> </ul> <h5>List With One Item</h5> <ul class="container"> <li>1</li> </ul> <h5>List With Two Items</h5> <ul class="container"> <li>1</li> <li class="fixed">2</li> </ul>