简易二代身份证校验

二代身份证的最后一位数字为校验位，用js实现了校验功能

function IDnum_check(ID) {    var reg = /^\d{18}$/;    var pass = true;    if(reg.test(ID) == false) {        pass= false;        return false;    }    else {        var code = ID.toString().split("");                    //权重因子        var factor = [ 7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2 ];                    //校验位        var parity = [ 1, 0, 'X', 9, 8, 7, 6, 5, 4, 3, 2 ];        var sum = 0;        for(var i = 0; i < 17; i++)        {            sum += code[i] * factor[i];        }        if(code[17] != parity[sum%11]) {            pass = false;            return false;        }        else            return true;    }}