Question

function changeStyling() {
  var para = document.getElementsByTagName("p");
  para[0].style.fontSize = 25;
  para[1].style.fontSize = "red";
}

<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>

<button onclick="changeStyling()">click</button>

Answer 1

应为fontSize="25px";和color="red"

function changeStyling() { 

  var para = document.getElementsByTagName("p");
  para[0].style.fontSize="25px"; 
  para[1].style.color="red"; 
}

<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<button onclick="changeStyling()">
    click
</button>

Answer 2

getElementsByTagName没什么问题，这是错误的地方：

对于字体大小，您需要指定一个单位，例如 px 。
要设置颜色，显然不能将 fontSize 设置为 color 。...

改进的代码：

function changeStyling() {
  var para = document.getElementsByTagName("p");
  para[0].style.fontSize = "25px";
  para[1].style.color = "red";
}

<p>This is paragraph 0</p>
<p>This is paragraph 1</p>
<p>This is paragraph 2</p>
<p>This is paragraph 3</p>

<button onclick="changeStyling()">click</button>

Answer 3

使用px设置字体大小

function changeStyling() {
  var para = document.getElementsByTagName("p");
  para[0].style.color = 'red';
  para[1].style.fontSize = '24px';

}

<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>

<button onclick="changeStyling()">
    click
</button>

Answer 4

getElementsByTagName正常工作。但是fontSize需要一个string。也要添加颜色，您需要为css属性设置颜色

function changeStyling() {
  var para = document.getElementsByTagName("p");
  para[0].style.fontSize = '25px';
  para[1].style.color = "red";


}

<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>
<p>This is the paragrap 1</p>

<button onclick="changeStyling()">
	    click
	</button>

Answer 5

function changeStyling() {


  var para = document.getElementsByTagName("p");
  // console.log(para);
  para[0].style.fontSize = '25px';
  para[1].style.color = "red";


}

<p> asdASDas </p>
<p> asdASDas </p>
<p> asdASDas </p>
<p> asdASDas </p>

<button onclick="changeStyling()"> push me </button>

尝试一下，我在fontSize内推入一个以像素为单位的字符串，并用红色为字符串着色。

Answer 6

您输入了错误的样式

para[0].style.fontSize = "25px"; // string with px
para[1].style.color = "red"; // color, instead of fontSize

JavaScript中的getElementsByTagName方法---不起作用

6 个答案: