Javascript 使用javascript计算元素的直接子元素
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Use javascript to count immediate child elements of an element
提问by Ark-of-Ice
I can get the count of all descendants of an element, but I can't seem to target just the immediatechildren. Here's what I have at the moment.
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的孩子。这是我目前所拥有的。
var sectionCount = document.getElementById("window").getElementsByTagName("section").length;
I've played with other stuff and different syntax, but I can't seem to get it.
我玩过其他东西和不同的语法，但我似乎无法理解。
The jQuery equivalent would be:
jQuery 等效项是：
var sectionCount = $("#window > section").length;
But I need to do this javascript only.
但我只需要做这个 javascript。
回答by Anurag
Use the DOM selector interface (querySelectorAll).
使用 DOM 选择器接口 ( querySelectorAll)。
var selectionCount = document.querySelectorAll("#window > section").length;
If you want a backwards compatible solution, loop through childNodesand count element nodes.
如果您想要一个向后兼容的解决方案，请循环遍历childNodes并计算元素节点。
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++;
}
}
