var
a = 10;
b = 20;
c = (a++,b++,100);
console.log(a);
console.log(b);
console.log(c);
值是11,21,100
大彻大悟了么?
关于运算符优先级问题可以查看:
https://developer.mozilla.org/zh-CN/docs/JavaScript/Reference/Operators/Operator_Precedence