.has()

jQuery

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.has()

Categories: Traversing > Filtering

.has( selector ) Returns: jQuery

Description: Reduce the set of matched elements to those that have a descendant that matches the selector or DOM element.

  • version added: 1.4.has( selector )

    • selector
      Type: String
      A string containing a selector expression to match elements against.

  • version added: 1.4.has( contained )

    • contained
      Type: Element
      A DOM element to match elements against.

Given a jQuery object that represents a set of DOM elements, the .has() method constructs a new jQuery object from a subset of the matching elements. The supplied selector is tested against the descendants of the matching elements; the element will be included in the result if any of its descendant elements matches the selector.

Consider a page with a nested list as follows:

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                                     <ul>
                                  

                                

                                

                                  

                                      <li>list item 1</li>
                                  

                                

                                

                                  

                                      <li>list item 2
                                  

                                

                                

                                  

                                        <ul>
                                  

                                

                                

                                  

                                          <li>list item 2-a</li>
                                  

                                

                                

                                  

                                          <li>list item 2-b</li>
                                  

                                

                                

                                  

                                        </ul>
                                  

                                

                                

                                  

                                      </li>
                                  

                                

                                

                                  

                                      <li>list item 3</li>
                                  

                                

                                

                                  

                                      <li>list item 4</li>
                                  

                                

                                

                                  

                                    
                                      </ul>

We can apply this method to the set of list items as follows:

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                                    $('li').has('ul').css('background-color', 'red');

The result of this call is a red background for item 2, as it is the only <li> that has a <ul> among its descendants.

Example:

Check if an element is inside another.

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                                        <!DOCTYPE html>
                                      
                                    

                                  

                                  

                                    

                                      
                                        <html>
                                      
                                    

                                  

                                  

                                    

                                      
                                        <head>
                                      
                                    

                                  

                                  

                                    

                                        <style>
                                    

                                  

                                  

                                    

                                        .full { border: 1px solid red; }
                                    

                                  

                                  

                                    

                                      
                                        </style>
                                      
                                    

                                  

                                  

                                    

                                        <script src="http://code.jquery.com/jquery-latest.js"></script>
                                    

                                  

                                  

                                    

                                      
                                        </head>
                                      
                                    

                                  

                                  

                                    

                                      
                                        <body>
                                      
                                    

                                  

                                  

                                    

                                       
                                    

                                  

                                  

                                    

                                      <ul><li>Does the UL contain an LI?</li></ul>
                                    

                                  

                                  

                                    

                                       
                                    

                                  

                                  

                                    

                                      
                                        <script>
                                        
                                      
                                    

                                  

                                  

                                    

                                        $("ul").append("<li>" + ($("ul").has("li").length ? "Yes" : "No") + "</li>");
                                    

                                  

                                  

                                    

                                        $("ul").has("li").addClass("full");
                                    

                                  

                                  

                                    

                                      
                                        </script>
                                      
                                    

                                  

                                  

                                    

                                       
                                    

                                  

                                  

                                    

                                      
                                        </body>
                                      
                                    

                                  

                                  

                                    

                                      
                                        </html>
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