JavaScript Tutorial/jQuery/jQuery

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Adds two functions into the jQuery namespace.

jQuery.extend({
  min: function(a, b) { return a < b ? a : b; },
  max: function(a, b) { return a > b ? a : b; }
});


Adds two plugin methods.

jQuery.fn.extend({
  check: function() {
    return this.each(function() { this.checked = true; });
  },
  uncheck: function() {
    return this.each(function() { this.checked = false; });
  }
});


Create Text node from query list

<html>
  <head>
    <script type="text/javascript" src="js/jquery-1.3.2.js"></script>
    <script type="text/javascript">
        $(document).ready(function(){
            
            var list = $("div,p,span").map(function () {
              return this.tagName;
            }).get().join(", ");
            
            
            $("b").append(document.createTextNode(list));

        });
    </script>
  </head>
  <body>
    <body>
          <span>span</span>
          <p>p</p>
          <div>div</div>
          <span>span</span>
    </body>
</html>


If jQuery is installed and running

<html>
  <head>
    <script type="text/javascript" src="js/jquery-1.3.2.js"></script>
    <script type="text/javascript">
if ($) {
  $(document).ready(
    function() {
      $("p").addClass("Loaded");
      $("p").text("jQuery loaded and running!");
    }
  );
}    
    </script>
    <style type="text/css">
p.Loaded {
    color: green;
    border: 1px solid green;
}    
    </style>
  </head>
  <body>
    <p>
        jQuery is not loaded.
    </p>
  </body>
</html>


Is jQuery ready

<html>
  <head>
    <script type="text/javascript" src="js/jquery-1.3.2.js"></script>
    <script type="text/javascript">
        $(document).ready(function(){
      var $ = "Hi!";
      jQuery(function($){
        alert("$ = "+ $);
      });
        });
    </script>
  </head>
  <body>
    <body>
        <p id="followMe">Follow me!</p>
    </body>
</html>


Pass array returned from jQuery to a function

<html>
  <head>
    <script type="text/javascript" src="js/jquery-1.3.2.js"></script>
    <script type="text/javascript">
        $(document).ready(function(){
               function disp(divs) {
                  var a = [];
                  for (var i = 0; i < divs.length; i++) {
                    a.push(divs[i].innerHTML);
                  }
                  alert(a.join(" "));
               }
                
               disp( $("p").get().reverse() );
        });
    </script>
  </head>
  <body>
    <body>
        <p>A</p><p>B</p>
    </body>
</html>


Show the order in the jQuery object.

<html>
  <head>
    <script type="text/javascript" src="js/jquery-1.3.2.js"></script>
    <script type="text/javascript">
        $(document).ready(function(){
            
            var list = $("div,p,span").map(function () {
              return this.tagName;
            }).get().join(", ");
            
            
            $("b").append(document.createTextNode(list));

        });
    </script>
  </head>
  <body>
    <body>
          <span>span</span>
          <p>p</p>
          <div>div</div>
          <span>span</span>
    </body>
</html>