← Back to jQuery Course | Chapter 2: Selectors | Lesson 8 of 10

Child Filter Selectors

The first-child filter selects elements that are first children.

In this page:

  1. First Child
  2. Last Child
  3. Only Child
  4. Nth Child
  5. Child Filters Together
Syntax
javascript 
$("selector:first-child")
$("selector:last-child")
$("selector:nth-child(n)")
$("selector:only-child")

First Child

':first-child' matches an element only when it is the very first child inside its parent, regardless of what tag it is. Note this differs from :first, which only ever matches within the current selection.

Example: First Child

javascript 
<!DOCTYPE html>
<html>
<head>
  <script src="https://code.jquery.com/jquery-3.7.1.min.js"></script>
  <style>
    button { padding:6px 14px; margin:4px; background:#2c6aa0; color:white; border:none; border-radius:4px; cursor:pointer; }
    #resetBtn { background:white; color:#2c6aa0; border:1px solid #2c6aa0; }
    #output { margin-top:10px; padding:8px; border:1px solid #ccc; border-radius:4px; background:#f7f7f7; font-family:monospace; min-height:24px; }
    #demo :where(p, div, span, li, h1, h2, h3, h4, td, th, blockquote, label, section, article, aside) { border:1px solid #4a7fb5; background:#eaf2fb; padding:6px 10px; margin:4px 0; border-radius:4px; }
    #demo :where(ul, ol) { border:1px dashed #888; background:#fafafa; padding:8px 8px 8px 32px; margin:6px 0; }
    #demo :where(table) { border-collapse:collapse; }
    #demo :where(td, th) { border-radius:0; }
    #demo :where(input, select, textarea) { margin:4px 0; }
  </style>
</head>
<body>
  <button id="runBtn">Run</button>
  <button id="resetBtn">Reset</button>
  <section id="demo">
    <ul><li>First</li><li>Second</li></ul>

  </section>
  <div id="output"></div>
  <script>
    var original = $("#demo").html();

    $("#runBtn").click(function() {
      $("#output").text($("li:first-child").text());
    });

    $("#resetBtn").click(function() {
      $("#demo").html(original);
      $("#output").empty();
    });
  </script>
</body>
</html>

Last Child

':last-child' is the mirror of :first-child -- it matches an element only when it's the final child of its parent, useful for styling or targeting the end of a list without knowing its length.

Example: Last Child

javascript 
<!DOCTYPE html>
<html>
<head>
  <script src="https://code.jquery.com/jquery-3.7.1.min.js"></script>
  <style>
    button { padding:6px 14px; margin:4px; background:#2c6aa0; color:white; border:none; border-radius:4px; cursor:pointer; }
    #resetBtn { background:white; color:#2c6aa0; border:1px solid #2c6aa0; }
    #output { margin-top:10px; padding:8px; border:1px solid #ccc; border-radius:4px; background:#f7f7f7; font-family:monospace; min-height:24px; }
    #demo :where(p, div, span, li, h1, h2, h3, h4, td, th, blockquote, label, section, article, aside) { border:1px solid #4a7fb5; background:#eaf2fb; padding:6px 10px; margin:4px 0; border-radius:4px; }
    #demo :where(ul, ol) { border:1px dashed #888; background:#fafafa; padding:8px 8px 8px 32px; margin:6px 0; }
    #demo :where(table) { border-collapse:collapse; }
    #demo :where(td, th) { border-radius:0; }
    #demo :where(input, select, textarea) { margin:4px 0; }
  </style>
</head>
<body>
  <button id="runBtn">Run</button>
  <button id="resetBtn">Reset</button>
  <section id="demo">
    <ul><li>First</li><li>Second</li></ul>

  </section>
  <div id="output"></div>
  <script>
    var original = $("#demo").html();

    $("#runBtn").click(function() {
      $("#output").text($("li:last-child").text());
    });

    $("#resetBtn").click(function() {
      $("#demo").html(original);
      $("#output").empty();
    });
  </script>
</body>
</html>

Only Child

':only-child' matches an element only when it has no sibling elements at all -- if the parent contains even one other child, this filter excludes it. This is a stricter check than :first-child or :last-child, since it requires there to be no siblings at all, not just no earlier or later ones.

Example: Only Child

javascript 
<!DOCTYPE html>
<html>
<head>
  <script src="https://code.jquery.com/jquery-3.7.1.min.js"></script>
  <style>
    button { padding:6px 14px; margin:4px; background:#2c6aa0; color:white; border:none; border-radius:4px; cursor:pointer; }
    #resetBtn { background:white; color:#2c6aa0; border:1px solid #2c6aa0; }
    #output { margin-top:10px; padding:8px; border:1px solid #ccc; border-radius:4px; background:#f7f7f7; font-family:monospace; min-height:24px; }
    #demo :where(p, div, span, li, h1, h2, h3, h4, td, th, blockquote, label, section, article, aside) { border:1px solid #4a7fb5; background:#eaf2fb; padding:6px 10px; margin:4px 0; border-radius:4px; }
    #demo :where(ul, ol) { border:1px dashed #888; background:#fafafa; padding:8px 8px 8px 32px; margin:6px 0; }
    #demo :where(table) { border-collapse:collapse; }
    #demo :where(td, th) { border-radius:0; }
    #demo :where(input, select, textarea) { margin:4px 0; }
  </style>
</head>
<body>
  <button id="runBtn">Run</button>
  <button id="resetBtn">Reset</button>
  <section id="demo">
    <div><p>Alone</p></div><div><p>A</p><p>B</p></div>

  </section>
  <div id="output"></div>
  <script>
    var original = $("#demo").html();

    $("#runBtn").click(function() {
      $("#output").text($("p:only-child").length);
    });

    $("#resetBtn").click(function() {
      $("#demo").html(original);
      $("#output").empty();
    });
  </script>
</body>
</html>

Nth Child

':nth-child(n)' selects children by their numeric position within their parent, and also accepts formulas like 2n or odd for picking out patterns such as every second row. This formula flexibility makes nth-child ideal for styling alternating table rows or picking out every third grid item.

Example: Nth Child

javascript 
<!DOCTYPE html>
<html>
<head>
  <script src="https://code.jquery.com/jquery-3.7.1.min.js"></script>
  <style>
    button { padding:6px 14px; margin:4px; background:#2c6aa0; color:white; border:none; border-radius:4px; cursor:pointer; }
    #resetBtn { background:white; color:#2c6aa0; border:1px solid #2c6aa0; }
    #output { margin-top:10px; padding:8px; border:1px solid #ccc; border-radius:4px; background:#f7f7f7; font-family:monospace; min-height:24px; }
    #demo :where(p, div, span, li, h1, h2, h3, h4, td, th, blockquote, label, section, article, aside) { border:1px solid #4a7fb5; background:#eaf2fb; padding:6px 10px; margin:4px 0; border-radius:4px; }
    #demo :where(ul, ol) { border:1px dashed #888; background:#fafafa; padding:8px 8px 8px 32px; margin:6px 0; }
    #demo :where(table) { border-collapse:collapse; }
    #demo :where(td, th) { border-radius:0; }
    #demo :where(input, select, textarea) { margin:4px 0; }
  </style>
</head>
<body>
  <button id="runBtn">Run</button>
  <button id="resetBtn">Reset</button>
  <section id="demo">
    <ul><li>1</li><li>2</li><li>3</li><li>4</li></ul>

  </section>
  <div id="output"></div>
  <script>
    var original = $("#demo").html();

    $("#runBtn").click(function() {
      $("li:nth-child(2n)").css("background", "lightgray");
    });

    $("#resetBtn").click(function() {
      $("#demo").html(original);
      $("#output").empty();
    });
  </script>
</body>
</html>

Child Filters Together

Chaining child filters with a parent selector, like '.list > li:nth-child(3)', combines structural position with tag or class context for precise, position-aware targeting. Layering selectors this way lets you target very specific elements, like 'the third item in this particular list', without adding extra classes to your markup.

Example: Child Filters Together

javascript 
<!DOCTYPE html>
<html>
<head>
  <script src="https://code.jquery.com/jquery-3.7.1.min.js"></script>
  <style>
    button { padding:6px 14px; margin:4px; background:#2c6aa0; color:white; border:none; border-radius:4px; cursor:pointer; }
    #resetBtn { background:white; color:#2c6aa0; border:1px solid #2c6aa0; }
    #output { margin-top:10px; padding:8px; border:1px solid #ccc; border-radius:4px; background:#f7f7f7; font-family:monospace; min-height:24px; }
    #demo :where(p, div, span, li, h1, h2, h3, h4, td, th, blockquote, label, section, article, aside) { border:1px solid #4a7fb5; background:#eaf2fb; padding:6px 10px; margin:4px 0; border-radius:4px; }
    #demo :where(ul, ol) { border:1px dashed #888; background:#fafafa; padding:8px 8px 8px 32px; margin:6px 0; }
    #demo :where(table) { border-collapse:collapse; }
    #demo :where(td, th) { border-radius:0; }
    #demo :where(input, select, textarea) { margin:4px 0; }
  </style>
</head>
<body>
  <button id="runBtn">Run</button>
  <button id="resetBtn">Reset</button>
  <section id="demo">
    <ul class="list"><li>1</li><li>2</li><li>3</li></ul>

  </section>
  <div id="output"></div>
  <script>
    var original = $("#demo").html();

    $("#runBtn").click(function() {
      $("#output").text($(".list > li:nth-child(3)").text());
    });

    $("#resetBtn").click(function() {
      $("#demo").html(original);
      $("#output").empty();
    });
  </script>
</body>
</html>
Related Topics

Visibility Filter Selectors · Form Filter Selectors · Content Filter Selectors · Basic Filter Selectors

{# common_mistakes/chapter_summary/browser_support: on Hindi pages the view already swaps in the hi_ translation fields (or blanks these out if untranslated), so this renders correctly for both languages without a lang_code check here. #}
Common Mistakes
  1. Confusing :first-child with :first, when li:first-child matches every <li> that is first in its parent and li:first returns only one match overall.
  2. Using :only-child on an element that has text siblings, forgetting it counts element siblings only.
  3. Counting :nth-child(n) from 0, when it starts from 1, so li:nth-child(1) is the first item.
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