Math.PI //圓周率
Math.floor () //向下取整
Math.ceil () //向上取整
Math.round () //四舍五入就近取整 注意﹣3.5 結(jié)果是-3
Math.abs () //絕對(duì)值
Math.max ()/Math.min() //求最大值和最小值
Math.random() //返回一個(gè)隨機(jī)的小數(shù) 0=<x<1(這個(gè)方法里面不跟參數(shù))

 //1.絕對(duì)值方法
        console.log(Math.abs(1)); // 1
        console.log(Math.abs(-1));  //1
        console.log(Math.abs('-5')); //5  會(huì)隱式轉(zhuǎn)換，將數(shù)字字符串轉(zhuǎn)換為數(shù)字，然后取絕對(duì)值
        console.log(Math.abs('aniu')); // NaN

//2.三個(gè)取整方法
        console.log(Math.floor(1.1)); //1
        console.log(Math.floor(1.9)); //1
        console.log(Math.floor(-1.1)); //-2
        console.log(Math.ceil(1.1));  // 2
        console.log(Math.ceil(1.9)); //2
        console.log(Math.ceil(-1.9)); //-1
        console.log(Math.round(1.5)); //2 四舍五入 .5這個(gè)特殊，是往大了取
        console.log(Math.round(-1.5)); // -1  往大了取
        console.log(Math.round(-1.2));  // -1

//3.求最大值/最小值
        console.log(Math.max(1,5,78,46));
        console.log(Math.min(1,5,78,46));

 //4.隨機(jī)數(shù)
        console.log(Math.random());

//核心算法
Math.floor(Math.random()*(max-min)) + min;

function getRandom(min,max){
            return Math.floor(Math.random()*(max-min)) + min;
        }
        console.log(getRandom(1,7));

//隨機(jī)點(diǎn)名
  var arr = ['阿牛','夢(mèng)夢(mèng)','小鳴人','winter','小何','WA','賤神','扎哇']  //太多啦，就寫(xiě)這些舉例啦
  console.log(arr);
  console.log('阿牛愛(ài)你們??????');
  function getRandom(min,max){
          return Math.floor(Math.random()*(max-min)) + min;
       }
  console.log('隨機(jī)點(diǎn)中了：' + arr[getRandom(0,arr.length - 1)]);