使用javascript為網頁增加夜間模式

HTML+CSS:

複製代碼代碼如下:

<div></div>

複製代碼代碼如下:

<style>

.cover{

position:fixed;

top: 0px;

left: 0px;

outline:5000px solid rgba(0, 0, 0, 0.3);

z-index: 99999;

}

</style>

接著用JavaScript寫個夜間模式plus:

複製代碼代碼如下:

<script>

var brightness;

//顯示遮罩

function cover(brightness) {

if (typeof(div) == 'undefined') {

div = document.createElement('div');

div.setAttribute('style', 'position:fixed;top:0;left:0;outline:5000px solid;z-index:99999;');

document.body.appendChild(div);

} else {

div.style.display = '';

}

div.style.outlineColor = 'rgba(0,0,0,' + brightness + ')';

}

//事件監聽

window.addEventListener('keydown', function(e) {

if (e.altKey && e.keyCode == 90) { //Alt+Z:打開夜間模式

cover(brightness = 0.3);

}

if (e.altKey && e.keyCode == 88) { //Alt+X:關閉

cover(brightness = 0);

}

if (e.altKey && e.keyCode == 38) { //Alt+↑:增加亮度

if (brightness - 0.05 > 0.05) cover(brightness -= 0.05);

}

if (e.altKey && e.keyCode == 40) { //Alt+↓:降低亮度

if (brightness + 0.05 < 0.95) cover(brightness += 0.05);

}

}, false);

</script>

還可以寫成GreaseMonkey腳本，作為瀏覽器擴展給任意頁面增加夜間模式