console.log('2021-9-28'.split('-')); // ["2021", "9", "28"]
console.log("日一二三四五六".charAt(0)); // 日
尚未写全,遇到在补充!!!
var arr = ['a', 'c', 'd', 'e', 'b', 'f']; console.log(arr.sort()); // ['a', 'b', 'c', 'd', 'e', 'f']
var arr1 = [6.17, 12, 17, 18] console.log(arr1.sort(function(a, b) { return a - b })); //升序 console.log(arr1.sort(function(a, b) { return b - a })); //降序
console.log(arr1.slice(1));
var arr2 = ['a', 'c', 'd', 'e', 'b', 'f']; console.log(arr2.indexOf('d')); console.log(arr2.lastIndexOf('f'));