不使用中间变量，交换int型的 a, b两个变量的值。

//by ppchen 
var a = 10, b = 2; 
a = a + b; 
b = a - b; 
a = a - b;

//by Mr.司马 
var a = 10000,b=245 
a = a^b; 
b = b^a; 
a = a ^b;

//by cloudgamer 
var a = 33,b=44 
a=[a,b] 
b=a[0] 
a=a[1]

//by Mr.司马 
var a = 23,b=454; 
a = {a:b,b:a}; 
b = a.b; 
a = a.a;

评：1、2种解法是普遍解，只能交换数字，而3、4种则适用性更广。