常用正则

function luhmCheck(bankno) {
    if(bankno.length < 16 || bankno.length > 19) {
        console.log("银行卡号长度必须在16到19之间");
        return false;
    }
    var num = /^\d*$/; //全数字
    if(!num.exec(bankno)) {
        console.log("银行卡号必须全为数字");
        return false;
    }
    //开头6位
    var strBin = "10,18,30,35,37,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,58,60,62,65,68,69,84,87,88,94,95,98,99";
    if(strBin.indexOf(bankno.substring(0, 2)) == -1) {
        console.log("银行卡号开头6位不符合规范");
        return false;
    }
    var lastNum = bankno.substr(bankno.length - 1, 1); //取出最后一位（与luhm进行比较）

    var first15Num = bankno.substr(0, bankno.length - 1); //前15或18位
    var newArr = new Array();
    for(var i = first15Num.length - 1; i > -1; i--) { //前15或18位倒序存进数组
        newArr.push(first15Num.substr(i, 1));
    }
    var arrJiShu = new Array(); //奇数位*2的积 <9
    var arrJiShu2 = new Array(); //奇数位*2的积 >9

    var arrOuShu = new Array(); //偶数位数组
    for(var j = 0; j < newArr.length; j++) {
        if((j + 1) % 2 == 1) { //奇数位
            if(parseInt(newArr[j]) * 2 < 9)
                arrJiShu.push(parseInt(newArr[j]) * 2);
            else
                arrJiShu2.push(parseInt(newArr[j]) * 2);
        } else //偶数位
            arrOuShu.push(newArr[j]);
    }

    var jishu_child1 = new Array(); //奇数位*2 >9 的分割之后的数组个位数
    var jishu_child2 = new Array(); //奇数位*2 >9 的分割之后的数组十位数
    for(var h = 0; h < arrJiShu2.length; h++) {
        jishu_child1.push(parseInt(arrJiShu2[h]) % 10);
        jishu_child2.push(parseInt(arrJiShu2[h]) / 10);
    }

    var sumJiShu = 0; //奇数位*2 < 9 的数组之和
    var sumOuShu = 0; //偶数位数组之和
    var sumJiShuChild1 = 0; //奇数位*2 >9 的分割之后的数组个位数之和
    var sumJiShuChild2 = 0; //奇数位*2 >9 的分割之后的数组十位数之和
    var sumTotal = 0;
    for(var m = 0; m < arrJiShu.length; m++) {
        sumJiShu = sumJiShu + parseInt(arrJiShu[m]);
    }

    for(var n = 0; n < arrOuShu.length; n++) {
        sumOuShu = sumOuShu + parseInt(arrOuShu[n]);
    }

    for(var p = 0; p < jishu_child1.length; p++) {
        sumJiShuChild1 = sumJiShuChild1 + parseInt(jishu_child1[p]);
        sumJiShuChild2 = sumJiShuChild2 + parseInt(jishu_child2[p]);
    }
    //计算总和
    sumTotal = parseInt(sumJiShu) + parseInt(sumOuShu) + parseInt(sumJiShuChild1) + parseInt(sumJiShuChild2);

    //计算Luhm值
    var k = parseInt(sumTotal) % 10 == 0 ? 10 : parseInt(sumTotal) % 10;
    var luhm = 10 - k;

    if(lastNum == luhm) {
        console.log("Luhm验证通过");
        return true;
    } else {
        console.log("银行卡号必须符合Luhm校验");
        return false;
    }
}