只在打印时出现指定内容
方案一:监听打印事件动态插入内容
操作步骤
Window.matchMedia() | MDN
MediaQueryList | MDN
matches | MDN
- 向
window.matchMedia(), 传入可用于媒体查询解析的字符串参数, - 返回一个
MediaQueryList实例, - 实例添加
change事件监听, - 判断当事件对象上的属性
matches - 为真是, 动态添加内容,
- 为假时,将添加的内容是移除
最小实现
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>print</title>
</head>
<body>
<script>
const print = window.matchMedia('print')
print.addEventListener('change', ({ matches }) => {
if (matches) {
const new = document.createElement('div')
new.className = 'new'
new.innerText = '会出现在打印界面的内容'
document.body.appendChild(new)
} else {
const new = document.querySelector('.new')
document.body.removeChild(new)
}
})
</script>
</body>
</html>
方案二:利用媒体查询针对性设置样式
最小实现
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>print</title>
<style>
.example {
display: none;
}
@media print {
.example {
display: block;
}
}
</style>
</head>
<body>
<p class="example">打印设备中显示</p>
</body>
</html>
