Addressing first/last item in an ul, li

How do you check whether a DOM element being clicked is either the 'first' li element or the 'l开发者_运维百科ast' li element in an unordered list item??

Based on your question as it appeared before your edit, as well as your comments, it seems you're responding to a li img being clicked, and trying to find out if that containing li is the first or last child.

Use .is() together with .closest() to check:

$('ul li img').click(function() {
    var $li = $(this).closest('li');

    if ($li.is(':first-child')) {
        // First
    } else if ($li.is(':last-child')) {
        // Last
    }
});

try this:

<ul class="myUnorderedList"><li>First</li><li>Last</li></ul>

js:

$('.myUnorderedList li').click(function(){

   if($(this).is(':first')) console.log('first li');
   if($(this).is(':last')) console.log('last li');

})

Use first() and last():

$('#ulid > li').first();
$('#ulid > li').last();

If this is your code:

<ul class="myUnorderedList"><li>First</li><li>Last</li></ul>

Then you can access it by the First selector (http://api.jquery.com/first-selector/) or last selector (enter link description here) as follows:

<script>$(".myUnorderedList>li:first").css("font-style", "italic");</script>

<script>$(".myUnorderedList>li:last").css("font-style", "italic");</script>

Maybe this could help

<ul>
  <li>one</li>
  <li>two</li>
  <li>three</li>
</ul>

With this jquery code

$("li").click(function(){
   if ($("li:first").text() == $(this).text() ){
      alert("first");
   }
  if ($("li:last").text() == $(this).text() ){
     alert("last");
  }
});

See it on http://jsfiddle.net/GT7Mm/