如何使这个显示/隐藏脚本有效？

Question

我是javascript的新手。我用我的noobie知识写了一个简单的show / hide off canvas脚本。它有效，但不是我想要的方式。我想在用户登录时显示左#mySidenav。它正在运行，但它隐藏了实际的信息中心内容，因为#main的行为与#mySidenav一样已关闭。我怎样才能做到这一点？

＆＃13;

＆＃13;

function openNav() {
  document.getElementById("mySidenav").style.width = "250px";
  document.getElementById("main").style.marginLeft = "250px";
  document.body.style.backgroundColor = "rgba(0,0,0,0.4)";
}

function closeNav() {
  document.getElementById("mySidenav").style.width = "0";
  document.getElementById("main").style.marginLeft = "0";
  document.body.style.backgroundColor = "white";
}

＆＃13;

body {
  font-family: "Lato", sans-serif;
  transition: background-color .5s;
}
.sidenav {
  height: 100%;
  width: 250px;
  position: fixed;
  z-index: 1;
  top: 0;
  left: 0;
  background-color: #111;
  overflow-x: hidden;
  transition: 0.5s;
  padding-top: 60px;
}
.sidenav a {
  padding: 8px 8px 8px 32px;
  text-decoration: none;
  font-size: 25px;
  color: #818181;
  display: block;
  transition: 0.3s
}
.sidenav a:hover,
.offcanvas a:focus {
  color: #f1f1f1;
}
.sidenav .closebtn {
  position: absolute;
  top: 0;
  right: 25px;
  font-size: 36px;
  margin-left: 50px;
}
#main {
  transition: margin-left .5s;
  padding: 16px;
}

＆＃13;

<div id="mySidenav" class="sidenav">
  <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">&times;</a>
  <a href="#">Employees</a>
  <a href="#">Schedules</a>
  <a href="#">Clients</a>
  <a href="#">Timesheets</a>
</div>

<div id="main">
  <h2>Admin Dashboard</h2>

  <span style="font-size:30px;cursor:pointer" onclick="openNav()">&#9776; open</span>
</div>

＆＃13;

＆＃13;

＆＃13;

Answer 1

如果您想默认打开sidenav，则必须为margin-left添加#main。试试这个：

body {
    font-family: "Lato", sans-serif;
    transition: background-color .5s;
    background-color:rgba(0,0,0,0.4)
}
#main {
        transition: margin-left .5s;
        padding: 16px;
        margin-left:250px;
}

如果您想默认关闭：

.sidenav {
    height: 100%;
    width: 0;
    position: fixed;
    z-index: 1;
    top: 0;
    left: 0;
    background-color: #111;
    overflow-x: hidden;
    transition: 0.5s;
    padding-top: 60px;
}

使用JsFiddle链接：https://jsfiddle.net/9u9hb839/11/

Answer 2

<div id="mySidenav" class="sidenav" style="width:0;">

或

.sidenav {
   width: 0px;
}

将宽度设置为0，它将停止在pageload

上默认打开sidenav

Answer 3

嗯，您需要在width:250px

中将width:0px更改为.sidenav

.sidenav {
  height: 100%;
  width: 0px;
}

它会阻止sidenav的默认打开。

function openNav() {
  document.getElementById("mySidenav").style.width = "250px";
  document.getElementById("main").style.marginLeft = "250px";
  document.body.style.backgroundColor = "rgba(0,0,0,0.4)";
}

function closeNav() {
  document.getElementById("mySidenav").style.width = "0";
  document.getElementById("main").style.marginLeft = "0";
  document.body.style.backgroundColor = "white";
}

body {
  font-family: "Lato", sans-serif;
  transition: background-color .5s;
}
.sidenav {
  height: 100%;
  width: 0px;
  position: fixed;
  z-index: 1;
  top: 0;
  left: 0;
  background-color: #111;
  overflow-x: hidden;
  transition: 0.5s;
  padding-top: 60px;
}
.sidenav a {
  padding: 8px 8px 8px 32px;
  text-decoration: none;
  font-size: 25px;
  color: #818181;
  display: block;
  transition: 0.3s
}
.sidenav a:hover,
.offcanvas a:focus {
  color: #f1f1f1;
}
.sidenav .closebtn {
  position: absolute;
  top: 0;
  right: 25px;
  font-size: 36px;
  margin-left: 50px;
}
#main {
  transition: margin-left .5s;
  padding: 16px;
}

<div id="mySidenav" class="sidenav">
  <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">&times;</a>
  <a href="#">Employees</a>
  <a href="#">Schedules</a>
  <a href="#">Clients</a>
  <a href="#">Timesheets</a>
</div>

<div id="main">
  <h2>Admin Dashboard</h2>

  <span style="font-size:30px;cursor:pointer" onclick="openNav()">&#9776; open</span>
</div>

Answer 4

也许你想要这个？

＆＃13;

＆＃13;

function openNav() {
  document.getElementById("mySidenav").style.width = "250px";
  document.getElementById("main").style.marginLeft = "250px";
  document.body.style.backgroundColor = "rgba(0,0,0,0.4)";
}

function closeNav() {
  document.getElementById("mySidenav").style.width = "0";
  document.getElementById("main").style.marginLeft = "0";
  document.body.style.backgroundColor = "white";
}

＆＃13;

body {
  font-family: "Lato", sans-serif;
  transition: background-color .5s;
}
.sidenav {
  height: 100%;
  width: 250px;
  position: fixed;
  z-index: 1;
  top: 0;
  left: 0;
  background-color: #111;
  overflow-x: hidden;
  transition: 0.5s;
  padding-top: 60px;
}
.sidenav a {
  padding: 8px 8px 8px 32px;
  text-decoration: none;
  font-size: 25px;
  color: #818181;
  display: block;
  transition: 0.3s
}
.sidenav a:hover,
.offcanvas a:focus {
  color: #f1f1f1;
}
.sidenav .closebtn {
  position: absolute;
  top: 0;
  right: 25px;
  font-size: 36px;
  margin-left: 50px;
}
#main {
  transition: margin-left .5s;
  padding: 16px;
  margin-left: 250px;
}

＆＃13;

<div id="mySidenav" class="sidenav">
  <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">&times;</a>
  <a href="#">Employees</a>
  <a href="#">Schedules</a>
  <a href="#">Clients</a>
  <a href="#">Timesheets</a>
</div>

<div id="main">
  <h2>Admin Dashboard</h2>

  <span style="font-size:30px;cursor:pointer" onclick="openNav()">&#9776; open</span>
</div>

＆＃13;

＆＃13;

＆＃13;

Answer 5

我建议尽可能使用CSS类，而不是直接在JS中使用值。这样可以避免在任何地方重复使用样式，并使代码更易于维护。我将如何做到这一点：

在正文中添加.nav-open课程

<body class="nav-open">

在CSS中添加这些样式

.sidenav{
    width: 0;
}

body.nav-open {
    background-color:rgba(0,0,0,0.4);
}

body.nav-open #main {
    margin-left: 250px;
}

body.nav-open .sidenav {
    width: 250px;
}

将您的JS更改为：

function openNav() {
  // Add the class
  document.body.className += " nav-open ";
}

function closeNav() {
  // Remove the class
  document.body.className = document.body.className.replace(/\bnav-open\b/g,' ');
}

演示

document.body.className = 'nav-open'; // Just for the demo

function openNav() {
  // Add the class
  document.body.className += " nav-open ";
}

function closeNav() {
  // Remove the class
  document.body.className = document.body.className.replace(/\bnav-open\b/g,' ');
}

body {
  font-family: "Lato", sans-serif;
  transition: background-color .5s;
}
.sidenav {
  height: 100%;
  width: 0;
  position: fixed;
  z-index: 1;
  top: 0;
  left: 0;
  background-color: #111;
  overflow-x: hidden;
  transition: 0.5s;
  padding-top: 60px;
}
.sidenav a {
  padding: 8px 8px 8px 32px;
  text-decoration: none;
  font-size: 25px;
  color: #818181;
  display: block;
  transition: 0.3s
}
.sidenav a:hover,
.offcanvas a:focus {
  color: #f1f1f1;
}
.sidenav .closebtn {
  position: absolute;
  top: 0;
  right: 25px;
  font-size: 36px;
  margin-left: 50px;
}
#main {
  transition: margin-left .5s;
  padding: 16px;
}
body.nav-open {
    background-color:rgba(0,0,0,0.4)
}

body.nav-open #main {
    margin-left: 250px;
}

body.nav-open .sidenav {
    width: 250px;
}

<div id="mySidenav" class="sidenav">
  <a href="#" class="closebtn" onclick="closeNav()">&times;</a>
  <a href="#">Employees</a>
  <a href="#">Schedules</a>
  <a href="#">Clients</a>
  <a href="#">Timesheets</a>
</div>

<div id="main">
  <h2>Admin Dashboard</h2>

  <span style="font-size:30px;cursor:pointer" onclick="openNav()">&#9776; open</span>
</div>

Answer 6

最简单的方法可能就是将openNav()更改添加到默认的HTML / CSS中，以便在页面加载时看到openNav()状态。

function openNav() {
  document.getElementById("mySidenav").style.width = "250px";
  document.getElementById("main").style.marginLeft = "250px";
  document.body.style.backgroundColor = "rgba(0,0,0,0.4)";
}

function closeNav() {
  document.getElementById("mySidenav").style.width = "0";
  document.getElementById("main").style.marginLeft = "0";
  document.body.style.backgroundColor = "white";
}

body {
  font-family: "Lato", sans-serif;
  transition: background-color .5s;
  background-color: rgba(0,0,0,0.4);
}
.sidenav {
  height: 100%;
  width: 250px;
  position: fixed;
  z-index: 1;
  top: 0;
  left: 0;
  background-color: #111;
  overflow-x: hidden;
  transition: 0.5s;
  padding-top: 60px;
}
.sidenav a {
  padding: 8px 8px 8px 32px;
  text-decoration: none;
  font-size: 25px;
  color: #818181;
  display: block;
  transition: 0.3s
}
.sidenav a:hover,
.offcanvas a:focus {
  color: #f1f1f1;
}
.sidenav .closebtn {
  position: absolute;
  top: 0;
  right: 25px;
  font-size: 36px;
  margin-left: 50px;
}
#main {
  transition: margin-left .5s;
  padding: 16px;
  margin-left: 250px;
}

<div id="mySidenav" class="sidenav">
  <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">&times;</a>
  <a href="#">Employees</a>
  <a href="#">Schedules</a>
  <a href="#">Clients</a>
  <a href="#">Timesheets</a>
</div>

<div id="main">
  <h2>Admin Dashboard</h2>

  <span style="font-size:30px;cursor:pointer" onclick="openNav()">&#9776; open</span>
</div>