如何在javascript中遍历子对象? [英] How do I loop through children objects in javascript?

问题描述

我在函数中有以下代码:

I have this code in a function:

tableFields = tableFields.children;
for (item in tableFields) {
    // Do stuff
}

根据tableFields的console.log，我得到一个数组，就像我想做的那样.循环中的项的console.log返回未定义.我该怎么做才能遍历tableFields并将每个对象插入表中?

According to a console.log of tableFields, I am getting an array back as I assume I need to do. A console.log of item within the loops returns undefined. What do I have to do to loop through tableFields and insert each object into a table?

tableFields的控制台日志:

console log of tableFields:

HTMLCollection[label, input, label, input 25, label, input, input, input Remove]


0
label

1
input

2
label

3
input 25

4
label

5
input

6
input

7 
input Remove

description[]
input

hours[]
input

invoice_number
input

getlength
8

rate[]
input 25

item
item()

iterator
iterator()

namedItem
namedItem()

__proto__
HTMLCollectionPrototype { item=item(), namedItem=namedItem(), iterator=iterator()}

这是到目前为止的整个代码部分:

Here is the entire section of code as I have so far:

$this->title("Test");
    $this->defaultMenu();
    $select = "";
    $names = Customer::getNames();
    foreach ($names as $id => $name) {
        $select .= '<option value="'.$id.'"';
        if ($this->customerid == $id) $select .= ' selected ';
        $select .= '>'.$name.'</option>';
    }

    $form = '
<script type="text/javascript">

var counter = 0;

function isEven(int){
int = Number(int);
return (int%2 == 0);
}



function moreLabor() {

    var table = document.getElementById("editTable");
    var tableFields = document.getElementById("readroot");

    tableFields = tableFields.children;
    console.log(tableFields);
    for (item in tableFields) {

        if (isEven(counter)) {
            var tableRow = table.insertRow(-1);
            var label = tableRow.insertCell(-1);
            console.log(tableFields[item]);
            label.appendChild(tableFields[item]);

        } else {
            var field = tableRow.insertCell(-1);
            field.innerHTML = item.innerHTML;


        }

        counter++;
    }

    console.log();
var insertHere = document.getElementById("writeroot");
}

window.onload = function(){
    document.getElementById(\'moreLabor\').onclick = function(){ moreLabor(); }
    moreLabor();
}


</script>

<div id="readroot" style="display: none">
<tr>
    <td><label for="hours">Hours:</label></td>
    <td><input type="text" name="hours[]" value="" /></td>
</tr>
<tr>
    <td><label for="rate">Rate:</label></td>
    <td><input type="text" name="rate[]" value="25" /></td>
</tr>
<tr>
    <td><label for="description">Description:</label></td>
    <td><input type="text" name="description[]" value="" /></td>
</tr>

<input type="hidden" name="invoice_number" value="'.$this->number.'" />
<tr>
    <td><input type="button" value="Remove"
    onclick="this.parentNode.parentNode.removeChild(this.parentNode);" /></td>
</tr>

</div>

<form method="POST" class="invoice" id="edit">
<table id="editTable">
    <tr>
        <td><label>Work Order Number:</label></td>
        <td><input type="text" name="number" value="'.$this->number.'"/></td>
    </tr>
    <tr>
        <td><label>Customer:</label></td>
        <td><select name="customerid">'.$select.'</select></td>
    </tr>
    <span id="writeroot"></span>

    <tr>
        <td><input type="button" id="moreLabor" value="Add labor"/></td>
        <td><input type="submit" name="Save" value="Save" /></td>
    </tr>';
    if (!is_null($this->id)) {
        $form .= '<input type="hidden" name="id" value="'.$this->id.'"/>';
    }
    $form .= '</table></form>';



    $this->component($form);

推荐答案

诀窍是 DOM Element.children 属性不是数组，而是一个类似于数组的集合，该集合具有长度并且可以像数组一样被索引，但不是数组:

The trick is that the DOM Element.children attribute is not an array but an array-like collection which has length and can be indexed like an array, but it is not an array:

var children = tableFields.children;
for (var i = 0; i < children.length; i++) {
  var tableChild = children[i];
  // Do stuff
}

顺便说一句，通常，使用基本的for循环而不是for-in-loop遍历数组是一种更好的做法.

Incidentally, in general it is a better practice to iterate over an array using a basic for-loop instead of a for-in-loop.

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