Par*_*ode 6 html javascript css
在这里，我试图隐藏该块，但第一次我需要在每次刷新页面时双击该按钮。我在下面附上了我的代码以供参考。
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
#myDIV {
width: 100%;
padding: 50px 0;
text-align: center;
background-color: lightblue;
margin-top: 20px;
display: none;
}
</style>
</head>
<body>
<p>Click the "Try it" button to toggle between hiding and showing the DIV element:</p>
<button onclick="myFunction()">Try it</button>
<div id="myDIV">
This is my DIV element.
</div>
<p><b>Note:</b> The element will not take up any space when the display property set to "none".</p>
<script>
function myFunction() {
var x = document.getElementById("myDIV");
if (x.style.display == "none") {
x.style.display = "block";
} else {
x.style.display = "none";
}
}
</script>
</body>
</html>
为什么会这样？有人可以让我知道我在哪里犯了错误吗？
第一次单击时，由于 CSS 的原因，页面上找不到 div 元素display: none。所以第一个 if 块没有被执行。它将元素设置display为none第一次单击，第二次单击时将值更改为block。
因此，我们需要在第一次点击时检查display属性值是否为none或""。
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
#myDIV {
width: 100%;
padding: 50px 0;
text-align: center;
background-color: lightblue;
margin-top: 20px;
display: none;
}
</style>
</head>
<body>
<p>Click the "Try it" button to toggle between hiding and showing the DIV
element:</p>
<button onclick="myFunction()">Try it</button>
<div id="myDIV">
This is my DIV element.
</div>
<p><b>Note:</b> The element will not take up any space when the display
property set to "none".</p>
<script>
function myFunction() {
var x = document.getElementById("myDIV");
if (x.style.display === "none" || x.style.display === "") {
x.style.display = "block";
} else {
x.style.display = "none";
}
}
</script>
</body>
</html>