Select deepest child in jQuery

Question

Is there a cheap method to select the deepest child of an element ?

Example:

<div id="SearchHere">
  <div>
    <div>
      <div></div>
    </div>
  </div>
  <div></div>
  <div>
    <div>
      <div>
        <div id="selectThis"></div>
      </div>
    </div>
  </div>
  <div>
    <div></div>
  </div>
</div>

Answer 1

EDIT: This is likely a better approach than my original answer:

Example: http://jsfiddle.net/patrick_dw/xN6d5/5/

var $target = $('#SearchHere').children(),
    $next = $target;

while( $next.length ) {
  $target = $next;
  $next = $next.children();
}

alert( $target.attr('id') );

or this which is even a little shorter:

Example: http://jsfiddle.net/patrick_dw/xN6d5/6/

var $target = $('#SearchHere').children();

while( $target.length ) {
  $target = $target.children();
}

alert( $target.end().attr('id') ); // You need .end() to get to the last matched set

---

Original answer:

This would seem to work:

Example: http://jsfiddle.net/xN6d5/4/

var levels = 0;
var deepest;

$('#SearchHere').find('*').each(function() {
    if( !this.firstChild || this.firstChild.nodeType !== 1  ) {
        var levelsFromThis = $(this).parentsUntil('#SearchHere').length;
        if(levelsFromThis > levels) {
            levels = levelsFromThis;
            deepest = this;
        }
    }
});

alert( deepest.id );

If you know that the deepest will be a certain tag (or something else), you could speed it up by replacing .find('*') with .find('div') for example.

EDIT: Updated to only check the length if the current element does not have a firstChild or if it does, that the firstChild is not a type 1 node.

Answer 2

Here's a slight improvement on the answer from @user113716, this version handles the case when there are no children and returns the target itself.

 (function($) {

    $.fn.deepestChild = function() {
        if ($(this).children().length==0)
            return $(this);

        var $target = $(this).children(),
        $next = $target;

        while( $next.length ) {
          $target = $next;
          $next = $next.children();
        }

        return $target;
    };

}(jQuery));

Answer 3

I don't think you can do it directly but you can try

var s = "#SearchHere";
while($(s + " >div ").size() > 0)
    s += " > div";
alert( $(s).attr('id') );

Answer 4

This chainable one-liner worked for me, but it assumes there is only one leaf node in the hierarchy below.

jQuery("#searchBeginsHere")
  .filter(function(i,e){ return jQuery(e).children().size() === 0; })

Answer 5

Version to get deepest for each leaf.

http://jsfiddle.net/ncppk0zw/14/

var found = $('#SearchHere *');

for (var i = 0; i < found.length; i++) {
    if (i > 1) {
        if (found[i].parentNode !== found[i-1]) {
            // Deepest. Next element is other leaf
            console.log(found[i-1]);
            continue;
        }
        if (i == found.length-1) {
            // Deepest. Last element in DOM tree
            console.log(found[i]);
        }
    }
}

Answer 6

This will find the deepest element of type "param" on the page. Useful if you are looking for the deepest , or whatever.

function deepest_child(param) {
    var element_list = $(param)
    var depth = 0
    var deepest_element
    element_list.each(
        function (index) {
            this_depth = $(this).parents().length
            if (this_depth > depth) {
                depth = this_depth 
                deepest_element= $(this)
            }
        })  
    return deepest_element
}

Answer 7

There is Simple Way with CSS

just add space between Classes or Ids

#SearchHere #selectThis{
      width:100px;
      height:50px;
      background-color:red;
    }
    
    #SearchHere .blueItem{
      width:100px;
      height:50px;
      background-color:blue;
    }
    
    #SearchHere .lastItem{
      width:100px;
      height:50px;
      background-color:cyan;
    }
    
    #SearchHere .middleItem{
      width:100px;
      height:50px;
      background-color:black;
    }
    

<div id="SearchHere">
    <div>
        <div class="blueItem">
            
        </div>
    </div>
    <div class="middleItem"></div>
    <div>
        <div>
            <div>
                <div id="selectThis"></div>
            </div>
        </div>
    </div>
    <div class="lastItem">
        <div></div>
    </div>
</div>