使用javascript计算元素的直接子元素 [英] Use javascript to count immediate child elements of an element

问题描述

我可以获得一个元素的所有后代的数量，但我似乎不能只针对直接子元素.这是我目前所拥有的.

I can get the count of all descendants of an element, but I can't seem to target just the immediate children. Here's what I have at the moment.

var sectionCount = document.getElementById("window").getElementsByTagName("section").length;

我玩过其他东西和不同的语法，但我似乎无法理解.

I've played with other stuff and different syntax, but I can't seem to get it.

jQuery 等效项是:

The jQuery equivalent would be:

var sectionCount = $("#window > section").length;

但我只需要执行这个 javascript.

But I need to do this javascript only.

推荐答案

使用 DOM 选择器接口 (querySelectorAll).

Use the DOM selector interface (querySelectorAll).

var selectionCount = document.querySelectorAll("#window > section").length;

如果你想要一个向后兼容的解决方案，循环遍历 childNodes 并计算元素节点.

If you want a backwards compatible solution, loop through childNodes and count element nodes.

var w = document.getElementById('window');
var count = 0; // this will contain the total elements.
for (var i = 0; i < w.childNodes.length; i++) {
    var node = w.childNodes[i];
    if (node.nodeType == Node.ELEMENT_NODE && node.nodeName == "SECTION") {
        count++;
    }
}

这篇关于使用javascript计算元素的直接子元素的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！