//四舍五入
var res = Math.round(5.64321);
//获取最大值
var res = Math.max(10,20,30,40,55,66,72,32);
//获取最小值
var res = Math.min(12312,324,32,42,3,23,412,4332,21,3,-1);
//获取绝对值
var res = Math.abs(-100);
//退一取整
var res = Math.floor(1.9);
//进一取整
var res = Math.ce
