只需20行代码就可以写出CSS覆盖率测试脚本_基础知识

for(var i = sheets.length - 1; i != -1; i--) {
    var rules = sheets[i].rules;

    for(var j = rules.length - 1; j != -1; j--) {
        var rule = rules[j];
        var text = rule.selectorText;

        usage.push({name: text, count: document.querySelectorAll(text).length});
    }
}
usage.sort(function(a, b){return a.count - b.count});

for(var i = usage.length - 1; i != -1; i--) {
    console.log("选择器：" + usage[i].name + "\n\t匹配数：" + usage[i].count);
}