Use JavaScript to add night mode _javascript tips for Web pages

HTML+CSS:

Copy Code code as follows:

<div class= "Cover" ></div>

Copy Code code as follows:

<style>
. cover{
position:fixed;
top:0px;
left:0px;
outline:5000px solid Rgba (0, 0, 0, 0.3);
z-index:99999;
}
</style>

Then write a nightly pattern plus in javascript:

Copy Code code as follows:

<script>
var brightness;
Show Matte
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 + ') ';
}
Event Monitoring
Window.addeventlistener (' KeyDown ', function (e) {
if (e.altkey && E.keycode = =) {//alt+z: Open night Mode
Cover (brightness = 0.3);
}
if (e.altkey && e.keycode =) {//alt+x: Off
Cover (brightness = 0);
}
if (e.altkey && E.keycode = =) {//alt+↑: Increase brightness
if (brightness-0.05 > 0.05) cover (brightness-= 0.05);
}
if (e.altkey && E.keycode = =) {//alt+↓: Lower brightness
if (brightness + 0.05 < 0.95) Cover (brightness = 0.05);
}
}, False);
</script>

Can also be written as a Greasemonkey script, extended as a browser to any page to increase the night mode