这个问题相当简单。我想检查浏览器是否支持焦点可见(
:focus-visible
)或不使用 JavaScript。我该怎么做?
console.log(selectorSupported(":focus-visible"))
function selectorSupported(selector){
var support, link, sheet, doc = document,
root = doc.documentElement,
head = root.getElementsByTagName('head')[0],
impl = doc.implementation || {
hasFeature: function() {
return false;
}
},
link = doc.createElement("style");
link.type = 'text/css';
(head || root).insertBefore(link, (head || root).firstChild);
sheet = link.sheet || link.styleSheet;
if (!(sheet && selector)) return false;
support = impl.hasFeature('CSS2', '') ?
function(selector) {
try {
sheet.insertRule(selector + '{ }', 0);
sheet.deleteRule(sheet.cssRules.length - 1);
} catch (e) {
return false;
}
return true;
} : function(selector) {
sheet.cssText = selector + ' { }';
return sheet.cssText.length !== 0 && !(/unknown/i).test(sheet.cssText) && sheet.cssText.indexOf(selector) === 0;
};
return support(selector);
};
所有功劳来自 Modernizr https://gist.github.com/paulirish/441842。
每个支持
:focus-visible
的浏览器也支持 CSS.supports()
API。
所以这应该有效:
window.CSS && CSS.supports && CSS.supports("selector(:focus-visible)")
或者在 ECMAScript 2020 中:
window.CSS?.supports?.("selector(:focus-visible)")
try{document.querySelector(':focus-visible');}catch(e){console.log(':focus-visible not supported');};