JavaScript --数字Number的常用方法
toFixed(保留几位小数)
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<body><script>// Number// toFixed(保留几位小数)var price = 123.4var sum = price.toFixed(2)-0+100console.log(sum.toFixed(2))</script>
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Math对象 random返回一个0-1之间的随机数
Math.round（）四舍五入取整
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<body><script>// round四舍五入取整console.log(Math.round(4.46))console.log(Math.round(5.56))</script>
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Math.ceil（）向上取整 Math. floor（）向下取整
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<body><script>// ceil向上 floor向下console.log(Math.ceil(4.46))console.log(Math.round(5.56))</script>
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abs取绝对值
console.log(Math.abs(-10))
sqrt取平方根
console.log(Math.sqrt(25))
pow(底数，指数)
console.log(Math.pow(2,3)) 相当于2的3次方
min和max
console.log(Math.min(10,2,3,11,50))
console.log(Math.max(10,2,3,11,50))
PI 圆周率
console.log(Math.PI)
