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我在网上找到了这个教程，以帮助我通过以下链接了解 Jquery 的拖放功能与这个卡片映射小游戏...... http://www.elated.com/res/File/articles/development/javascript/jquery /drag-and-drop-with-jquery-your-essential-guide/card-game.html

在第 37 行，为什么 $('<div>' + numbers[i] + '</div>')在它还不存在的时候被选中，就我而言，当它们已经存在于文档中时，你在 Jquery 中选择它们.. 我不太明白那个选择器，有人可以请详细说明该选择器发生了什么？即使在第 48 行 ... 是uiJquery 中的内置词 .. 当他们说ui.draggable？究竟ui指的是什么？

谢谢 ！

<!doctype html>
<html lang="en">
<head>

<title>A jQuery Drag-and-Drop Number Cards Game</title>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8">
<link rel="stylesheet" type="text/css" href="style.css">

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.5.0/jquery.min.js"></script>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.9/jquery-ui.min.js"></script>
<script type="text/javascript">

var correctCards = 0;
$( init );

function init() {

  // Hide the success message
  $('#successMessage').hide();
  $('#successMessage').css( {
    left: '580px',
    top: '250px',
    width: 0,
    height: 0
  } );

  // Reset the game
  correctCards = 0;
  $('#cardPile').html( '' );
  $('#cardSlots').html( '' );

  // Create the pile of shuffled cards
  var numbers = [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ];
  numbers.sort( function() { return Math.random() - .5 } );

  for ( var i=0; i<10; i++ ) {
    $('<div>' + numbers[i] + '</div>').data( 'number', numbers[i] ).attr( 'id', 'card'+numbers[i] ).appendTo( '#cardPile' ).draggable( {
      containment: '#content',
      stack: '#cardPile div',
      cursor: 'move',
      revert: true
    } );
  }

  // Create the card slots
  var words = [ 'one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight', 'nine', 'ten' ];
  for ( var i=1; i<=10; i++ ) {
    $('<div>' + words[i-1] + '</div>').data( 'number', i ).appendTo( '#cardSlots' ).droppable( {
      accept: '#cardPile div',
      hoverClass: 'hovered',
      drop: handleCardDrop
    } );
  }

}

function handleCardDrop( event, ui ) {
  var slotNumber = $(this).data( 'number' );
  var cardNumber = ui.draggable.data( 'number' );

  // If the card was dropped to the correct slot,
  // change the card colour, position it directly
  // on top of the slot, and prevent it being dragged
  // again

  if ( slotNumber == cardNumber ) {
    ui.draggable.addClass( 'correct' );
    ui.draggable.draggable( 'disable' );
    $(this).droppable( 'disable' );
    ui.draggable.position( { of: $(this), my: 'left top', at: 'left top' } );
    ui.draggable.draggable( 'option', 'revert', false );
    correctCards++;
  } 

  // If all the cards have been placed correctly then display a message
  // and reset the cards for another go

  if ( correctCards == 10 ) {
    $('#successMessage').show();
    $('#successMessage').animate( {
      left: '380px',
      top: '200px',
      width: '400px',
      height: '100px',
      opacity: 1
    } );
  }

}

</script>

</head>
<body>

<div class="wideBox">
  <h1>Drag-and-Drop with jQuery: Your Essential Guide</h1>
  <h2>A Number Cards Game</h2>
</div>

<div id="content">

  <div id="cardPile"> </div>
  <div id="cardSlots"> </div>

  <div id="successMessage">
    <h2>You did it!</h2>
    <button onclick="init()">Play Again</button>
  </div>

</div>

<div class="wideBox">
  <p>&copy; Elated.com | <a href="http://www.elated.com/articles/drag-and-drop-with-jquery-your-essential-guide/">Back to Tutorial</a></p>
  <p style="font-size: .8em; line-height: 1.5em;"><a rel="license" href="http://creativecommons.org/licenses/by/3.0/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by/3.0/88x31.png" /></a><br />This <span xmlns:dc="http://purl.org/dc/elements/1.1/" href="http://purl.org/dc/dcmitype/Text" rel="dc:type">work</span> by <a xmlns:cc="http://creativecommons.org/ns#" href="http://www.elated.com/" property="cc:attributionName" rel="cc:attributionURL">http://www.elated.com/</a> is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by/3.0/">Creative Commons Attribution 3.0 Unported License</a>.</p>
</div>

</body>
</html>
4

2 回答 2

4

表达方式：

    $('<div>' + numbers[i] + '</div>')

不是选择器。当 to 的参数jQuery是一段 HTML（即以 开头<）时，它会创建对应于 HTML 的新 DOM 元素，它不会在 DOM 中搜索它们。

$("div")是选择者，$("<div>")是创造者。

ui是一个变量名，它是handleCardDrop函数的第二个参数。由于此函数是 jQuery UIDraggable小部件使用的回调，它接收实例作为参数，ui.draggable然后可用于引用小部件的功能。

于 2013-07-25T17:08:06.063 回答
1 
$('<div>' + numbers[i] + '</div>')

它创建新元素，而不是在页面上选择.. 就像 document.createElement

于 2013-07-25T17:07:55.867 回答