// 处理数字
var e =eval("0.1+0.2")
var C = e
console.log(C.toString().length)
console.log(C)
console.log((100 * C).toPrecision(12))
console.log(typeof(C)+":"+C)
var a = parseFloat((100 * C).toPrecision(12))
console.log(typeof(a)+":"+a)
console.log([2,3,4,5,6].splice(3,1))