如何在 for 循环中 getElementsByTagName

Question

我尝试这样做。但未能成功。请帮忙。

var myP = document.getElementsByTagName('p');
for (var i = 0; i < myP.lenght; myP++) {
  myP[i].style.color = red;
}

<div id="wrap">
  <p>first paragraph </p>
  <p>2nd paragraph </p>
  <p>3rd paragraph </p>
</div>

Answer 1

代码存在三个问题。第一：

myP.lenght

应该是

myP.length

。第二：您正在增加

myP

，您应该增加

i

，第三个：

style.color

应该是

"red"

而不是

red

。

var myP = document.getElementsByTagName('p');
for (var i = 0; i < myP.length; i++) { // should be i++
  myP[i].style.color = "red"; // color = "red"
}

<div id="wrap">
  <p>first paragraph </p>
  <p>2nd paragraph </p>
  <p>3rd paragraph </p>
</div>

Answer 2

var myP = document.getElementsByTagName('p');
for (var i = 0; i < myP.length; i++) { // <-- increment i, not myP
  myP[i].style.color = 'red'; // <-- string not variable
}

Answer 3

let elements = [...document.getElementsByTagName('p')];
elements.forEach((p) => {
  p.style.color = 'red';
});