我刚接触React,当我使用以下代码添加一个侧边栏组件时,出现了以下错误:
无法读取null对象的'style'属性
import React, { Component } from "react";
import "../css/sidebar.css";
class Sidebar extends Component {
state = {};
openNav() {
document.getElementById("mySidenav").style.width = "250px";
document.getElementById("main").style.marginLeft = "250px";
}
closeNav() {
document.getElementById("mySidenav").style.width = "0";
document.getElementById("main").style.marginLeft = "0";
}
render() {
return (
<div>
<div id="mySidenav" class="sidenav">
<a
href="javascript:void(0)"
class="closebtn"
onclick={this.closeNav()}
>
×
</a>
<a href="#">About</a>
<a href="#">Services</a>
<a href="#">Clients</a>
<a href="#">Contact</a>
</div>
<div id="main">
<h2>Sidenav Push Example</h2>
<p>
Click on the element below to open the side navigation menu, and
push this content to the right.
</p>
<span
styles={{ fontSize: "30", cursor: "pointer" }}
onclick={this.openNav()}
>
☰ open
</span>
</div>
</div>
);
}
}
export default Sidebar;
下面部分是否有错误?
document.getElementById("mySidenav").style.width = "0";
问题是什么?
如果有人能够帮忙解决,将非常感激。