Years may wrinkle the skin, but to give up enthusiasm wrinkles the soul.
歲月留痕，只及肌膚；激情不再，皺起心靈。———— Samuel Ullman
學(xué)習(xí)javascript，用雙for和雙while循環(huán)輸出小九九乘法表：1.雙for循環(huán)var xvar yfor(x=1;x