` 模板字符串，告别打印输出多行
反撇号（`） 反单引号
var user = {name: Vicent};
console.log(`my name is ${user.name}`);
打印结果：my name is Vicent
http://www.infoq.com/cn/articles/es6-in-depth-template-string
var user = {name: Vicent};
console.log(`my name is ${user.name}`);
打印结果：my name is Vicent
http://www.infoq.com/cn/articles/es6-in-depth-template-string