getElementsByTagName()方法无法按预期工作 [英] getElementsByTagName() method doesnt work as expected
问题描述
我正在尝试使用此代码简单地更改所有</p>元素内的文本
I'm trying to simply change the text inside all </p> elements with this code
<html>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/css/bootstrap.min.css">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/js/bootstrap.min.js"></script>
<body>
<p></p>
<script>
elem=document.getElementsByTagName("p");
elem.innerHTML="work";
</script>
</body>
</html>
据此，我希望work出现在页面上，但结果只是空白页面没有文本.为什么?
from this I expect work to appear on the page, but the result is just a blank page with no text. why?
推荐答案
getElementsByTagName是DOM接口的方法.接受标签 名称作为输入并返回NodeList(某些浏览器选择返回 而是HTMLCollection，这没关系，因为它是的超集 NodeList).
getElementsByTagName is method of the DOM interface. It accepts a tag name as input and returns a NodeList (some browsers chose to return HTMLCollection instead, which is OK, since it is a superset of NodeList).
HTMLCollection，NodeList和对象数组之间的区别
您必须设置HTMLCollection/NodeList的索引.
You have to set the index of your HTMLCollection/NodeList.
elem=document.getElementsByTagName("p");
elem[0].innerHTML="work";
您还可以为HTML文档中的每个p标签执行此操作.
You can also do it for each p tag in your HTML document.
var elem = document.getElementsByTagName("p");
for(var index = 0; index < elem.length; index++){
elem[index].innerHTML="work";
}
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