← Back to jQuery Course | Chapter 2: Selectors | Lesson 5 of 10

Basic Filter Selectors

The first filter selects the first matching element.

In this page:

  1. First Filter
  2. Last Filter
  3. Even and Odd
  4. Equal Filter
  5. Not Filter
Syntax
javascript 
$("selector:first")
$("selector:last")
$("selector:even")
$("selector:odd")
$("selector:eq(index)")

First Filter

Appending :first to a selector narrows a multi-element match down to just the very first element in document order. It's equivalent to using :eq(0) but reads more clearly.

Since jQuery evaluates filters after the base selector runs, :first still requires jQuery to first find every match before narrowing down.

Example: First Filter

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">
    <li>A</li><li>B</li><li>C</li>

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

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

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

Last Filter

The :last filter is the mirror image of :first -- it keeps only the final matching element in document order, discarding every match before it. This is commonly combined with a base selector, like 'li:last', to grab the final item in a specific list.

Example: Last Filter

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">
    <li>A</li><li>B</li><li>C</li>

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

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

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

Even and Odd

':even' and ':odd' use zero-based indexing, so ':even' actually selects the 1st, 3rd, 5th... elements visually, since index 0 counts as even -- a common source of off-by-one confusion for beginners.

Example: Even and Odd

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">
    <li>A</li><li>B</li><li>C</li><li>D</li>

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

    $("#runBtn").click(function() {
      $("li:even").css("background", "yellow");
    });

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

Equal Filter

':eq(n)' selects a single element at a specific zero-based position in the match set, giving you precise control when :first and :last aren't specific enough. Because positions are zero-based, :eq(2) actually selects the third matching element, not the second.

Example: Equal Filter

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">
    <li>A</li><li>B</li><li>C</li>

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

    $("#runBtn").click(function() {
      $("#output").text($("li:eq(2)").text());
    });

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

Not Filter

':not(selector)' excludes any element matching the inner selector from the result, letting you select 'everything except' a particular group in one expression. This is especially handy for styling 'every button except the currently active one' without manually excluding it in your markup.

Example: Not Filter

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; }
    .btn { display:inline-block; padding:6px 14px; margin:4px; background:#2c6aa0; color:white; border-radius:4px; cursor:pointer; font:13px sans-serif; }
    #resetBtn.btn { background:white; color:#2c6aa0; border:1px solid #2c6aa0; }
    #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>
  <span id="runBtn" class="btn" role="button">Run</span>
  <span id="resetBtn" class="btn" role="button">Reset</span>
  <section id="demo">
    <button class="active">A</button><button>B</button><button>C</button>

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

    $("#runBtn").click(function() {
      $("button:not(.active)").css("opacity", "0.5");
    });

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

Content Filter Selectors · Visibility Filter Selectors · Child Filter Selectors · Form 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. Believing :even selects the 2nd, 4th, 6th items, when indexes start at 0 so li:even matches the 1st, 3rd and 5th.
  2. Using :eq(1) expecting the first item; indexes are zero-based, so :eq(0) is the first.
  3. Writing $("li:first") for the first item of each list, when it returns only one element on the whole page; :first-child matches one per parent.
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