JS保留3位小数_保留一位小数表示精确到几位

function name(params) {

    let newpar = parseFloat(params);

    let reg = /^[0-9]+.?[0-9]*$/;

    if(reg.test(newpar)){

        let newNum = newpar.toFixed(3);

        return newNum;

    }else{

        alert('请输入数字');

        return;

    }

}

toThousands: function (num) {

    var num = (num || 0).toString(), result = '';

    while (num.length > 3) {

        result = ',' + num.slice(-3) + result;

        num = num.slice(0, num.length - 3);

    }

    if (num) { result = num + result; }

    return result;

},