javascript 正则问题

Question

var str = "For more information, see Chapter 3.4.5.1";var re = /(chapter \d+(\.\d)*)/i;var found = str.match(re);console.log(found);捕获到了3个结果 ： ["Chapter 3.4.5.1", "Chapter 3.4.5.1", ".1"]而我认为结果应该只有一个 ["Chapter 3.4.5.1"],请问为什么会有3个?