Question

我正在开发一款可向用户展示调查问题的应用。标记看起来像这样：

<body>
    <div class="question" id="q1">
        Question 1
    </div>
    <div class="question" id="q2">
        Question 2
    </div>
    <!-- etc -->
</body>

我想使用jQuery从DOM构造JavaScript对象，因此在Survey构造函数中，我使用each()方法遍历jQuery集。问题是在回调函数中我无法获得对Survey对象的引用，以便将每个Question对象附加到Survey.questions数组。如何获得对Survey对象的引用？有没有办法将附加参数（例如对Survey对象的引用）传递给回调函数？

function Survey() {
    this.questions = new Array;
    $('.question').each(function(i) { (/* Survey object */).questions.push(new Question(this)); });
}

function Question(element) {
    this.element = $(element);
}

Answer 1

在迭代问题之前，您应该能够创建对调查的引用。

function Survey() {
    this.questions = new Array();
    var survey = this;
    $('.question').each(function(i) {
        survey.questions.push(new Question(this));
    });
}

function Question(element) {
    this.element = $(element);
}

var survey = new Survey();

$.each(survey.questions, function() {
    $("ul").append("<li>" + this.element.text() + "</li>");
});

jsfiddle

上的工作示例

Answer 2

虽然这可能不是相关的答案，但是问题是如何将参数传递给jQuery各个函数。

第一种方法：使用部分功能 - more on this 从closure library

jsfiddle：

var param = 'extra-param';   

var partial = function(fn, var_args) {
  var args = Array.prototype.slice.call(arguments, 1);
  return function() {
    // Clone the array (with slice()) and append additional arguments
    // to the existing arguments.
    var newArgs = args.slice();
    newArgs.push.apply(newArgs, arguments);
    return fn.apply(this, newArgs);
  };
};

$(['joe','james','rick','kirk']).each(partial (function (index,value) {
    alert(arguments.length);
    alert(arguments[0]);
 },param));

第二种方法是

$。每个函数可以使用2个参数Index和Element（也可以称为this）要么如果您不需要Index，那么您可以将Array作为参数传递给$ .each，元素可以称为此

注意：args仅供内部使用 - 通过jQuery

// Execute a callback for every element in the matched set.
// (You can seed the arguments with an array of args, but this is
// only used internally.)
each: function( callback, args ) {
    return jQuery.each( this, callback, args );
},

将调用each: function( obj, callback, args )

如果将数组作为参数传递，则调用callback.apply( obj[ i ], args ); 否则callback.call( obj[ i ], i, obj[ i ] );

请注意申请和致电的区别

示例代码：http://jsfiddle.net/dekajp/yA89R/1/

var param = 'rick';
$(['joe','james','rick','kirk']).each(function (arg1 , arg2 ,arg3) {
    //alert('[this: '+this +'] [arg1: '+ arg1 +'] [arg2:'+arg2+'] [param:'+param+']');
},['hello 1','hello 2','hello 3']);

参考jQuery每个代码版本1.9

// args is for internal usage only
    each: function( obj, callback, args ) {
        var value,
            i = 0,
            length = obj.length,
            isArray = isArraylike( obj );

        if ( args ) {
            if ( isArray ) {
                for ( ; i < length; i++ ) {
                    value = callback.apply( obj[ i ], args );

                    if ( value === false ) {
                        break;
                    }
                }
            } else {
                for ( i in obj ) {
                    value = callback.apply( obj[ i ], args );

                    if ( value === false ) {
                        break;
                    }
                }
            }

        // A special, fast, case for the most common use of each
        } else {
            if ( isArray ) {
                for ( ; i < length; i++ ) {
                    value = callback.call( obj[ i ], i, obj[ i ] );

                    if ( value === false ) {
                        break;
                    }
                }
            } else {
                for ( i in obj ) {
                    value = callback.call( obj[ i ], i, obj[ i ] );

                    if ( value === false ) {
                        break;
                    }
                }
            }
        }

        return obj;
    },

Answer 3

我遇到了类似的问题。将param传递给每个函数：

var param1 = "one";
var param2 = "two";

var params = [ param1, param2 ];


$( '#myTable > tbody  > tr' ).each(function( index ) {

     var param1back = params[0];
     var param2back = params[1];

},params);

Answer 4

//Create extra data
var dataArray = ["A", "B", "C"];

//Send default arguments from jQuery's each (index and item) along
//with our new data argument to a named function handler.
$("#myList").children().each(function(jqIndex, jqItem)
                            {
                              listItemsHandler(jqIndex, jqItem, dataArray[jqIndex]);
                            });    

//Named function handler accepting 3 arguments.
function listItemsHandler(index, item, data)
{
    console.log(index + " " + item + " " + data);
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<ol id = "myList">
  <li>First</li>
  <li>Second</li>
  <li>Third</li> 
</ol>

将其他参数传递给jQuery each（）回调

4 个答案: