如何在所有现代浏览器中检测页面缩放级别?虽然这篇文章讲述了如何在IE7和IE8中做到这一点，但我找不到一个好的跨浏览器解决方案。
Firefox存储页面缩放级别以供将来访问。在第一页加载，我能得到缩放级别吗?在某个地方，我读到当页面加载后发生缩放变化时，它是有效的。
有办法捕捉'缩放'事件吗?
我需要这个，因为我的一些计算是基于像素的，他们可能会在放大时波动。
@tfl给出的修改样本
放大时，此页面会提示不同的高度值。(jsFiddle)
<html>
<head>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.1/jquery.min.js" type="text/javascript"/></script>
</head>
<body>
<div id="xy" style="border:1px solid #f00; width:100px;">Lorem ipsum dolor sit amet, consectetur adipiscing elit. Pellentesque sollicitudin tortor in lacus tincidunt volutpat. Integer dignissim imperdiet mollis. Suspendisse quis tortor velit, placerat tempor neque. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Praesent bibendum auctor lorem vitae tempor. Nullam condimentum aliquam elementum. Nullam egestas gravida elementum. Maecenas mattis molestie nisl sit amet vehicula. Donec semper tristique blandit. Vestibulum adipiscing placerat mollis.</div>
<button onclick="alert($('#xy').height());">Show</button>
</body>
</html>
我修复了下面的代码。
HTML:
<div class="mt-5"
[ngStyle]="getStyles()">
TS:
getStyles() {
const screenWidth = screen.width;
const windowWidth = window.innerWidth;
if (windowWidth != screenWidth) {
const percentDifference = Math.ceil((screenWidth / windowWidth) * 100);
if (percentDifference > 100) {
this.bannerBackgroundImageSize = '20%, 74%';
} else if (percentDifference === 100) {
this.bannerBackgroundImageSize = '20%, 72%';
} else if (percentDifference >= 90 && percentDifference <= 99) {
this.bannerBackgroundImageSize = '25%, 70%';
} else if (percentDifference >= 80 && percentDifference <= 89) {
this.bannerBackgroundImageSize = '28%, 68%';
} else if (percentDifference >= 75 && percentDifference <= 79) {
this.bannerBackgroundImageSize = '29%, 67%';
} else if (percentDifference >= 67 && percentDifference <= 74) {
this.bannerBackgroundImageSize = '30%, 65%';
} else if (percentDifference >= 50 && percentDifference <= 66) {
this.bannerBackgroundImageSize = '30%, 61%';
} else if (percentDifference < 50) {
this.bannerBackgroundImageSize = '30%, 58%';
}
} else {
this.bannerBackgroundImageSize = '20%, 72%';
}
const myStyles = {
'background-size': this.bannerBackgroundImageSize,
};
return myStyles;
}
我希望这将适用于所有缩放级别，它可以考虑与所有风格。
一个变通的FireFox 16+找到DPPX(缩放级别)纯粹与JavaScript:
var dppx = (function (precision) {
var searchDPPX = function(level, min, divisor) {
var wmq = window.matchMedia;
while (level >= min && !wmq("(min-resolution: " + (level/divisor) + "dppx)").matches) {
level--;
}
return level;
};
var maxDPPX = 5.0; // Firefox 22 has 3.0 as maximum, but testing a bit greater values does not cost much
var minDPPX = 0.1; // Firefox 22 has 0.3 as minimum, but testing a bit smaller values does not cost anything
var divisor = 1;
var result;
for (var i = 0; i < precision; i++) {
result = 10 * searchDPPX (maxDPPX, minDPPX, divisor);
maxDPPX = result + 9;
minDPPX = result;
divisor *= 10;
}
return result / divisor;
}) (5);
