ECMAscript 6引入了
String.prototype.includes：
const string = "foo";const substring = "oo";console.log(string.includes(substring));
includes但是不支持
Internet Explorer。在ECMAscript 5或更旧的环境中，使用
String.prototype.indexOf，当找不到子字符串时，它将返回-1：
var string = "foo";var substring = "oo";console.log(string.indexOf(substring) !== -1);
