1.round(参数)：Math.round(0.60) 四舍五入=1；Math.round(-0.60) 四舍五入=-1；
2.random():返回 0 ~ 1 之间的随机数;
3.max(参数1，参数2)：返回两者的最大者；
4.min(参数1，参数2)：返回两者的最小者；
5.abs(参数)：返回数的绝对值。
6.ceil(参数)：向上取舍。
7.floor(参数)：向下取舍。
8.toSource()：返回对象的各个属性值。
function employee(name,job,born){this.name=name;this.job=job;this.born=born;}var bill=new employee("Bill Gates","Engineer",1985);document.write(bill.toSource());function employee(name,job,born){this.name=name;this.job=job;this.born=born;}var bill=new employee("Bill Gates","Engineer",1985);document.write(bill.toSource());
function employee(name,job,born){this.name=name;this.job=job;this.born=born;}var bill=new employee("Bill Gates","Engineer",1985);document.write(bill.toSource());function employee(name,job,born){this.name=name;this.job=job;this.born=born;}var bill=new employee("Bill Gates","Engineer",1985);document.write(bill.toSource());
