function MathFloatNumber(val1,val2,type){ //val1:浮点数1 val2:浮点数2 type:运算类型（+，-，*，/，=）
let intnumber1=String(val1).split('.')[1].length //浮点数转string并获取小数点后面位数
let intnumber2=String(val2).split('.')[1].length //浮点数转string并获取小数点后面位数
let biglength=Math.pow(10,(intnumber1>intnumber2?intnumber1:intnumber2)) //得到小数点位数多的数，计算浮点数转为整数的位数 （10的位数次方）
let bigval1=val1*biglength //得到放大倍数的浮点数1
console.log(biglength)
let bigval2=val2*biglength //得到放大倍数的浮点数2
switch(type){
case 1: //加法
return (bigval1+bigval2)/biglength /
break
case 2: //减法
return (bigval1-bigval2)/biglength
break
case 3: //乘法
return (bigval1*bigval2)/(biglength*biglength)
break
case 4: //除法
return (bigval1/bigval2).toFixed(3)
break
case 5:
return bigval1===bigval2
break
default:
console.log('类型错误')
}
}
// var a=MathFloatNumber(0.1,0.05,2)
// console.log(a)
console.log(MathFloatNumber(MathFloatNumber(0.1,0.2,1),0.3,5)) // 判断（0.1+0.2==0.3）等于true