javascript 判断一个数字是不是身份证号

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<script type="text/javascript">

    //

    // javascript 判断一个数字是不是身份证号

    // 代码摘自 http: //topic.csdn.net/u/20110102/22/e79df4e8-7b0a-4c65-9490-1ef39837ff36.html?8841

    function isChinaIDCard(StrNo) {

        StrNo = StrNo.toString()

        if (StrNo.length == 18) {

            var a, b, c

            if (!isInteger(StrNo.substr(0, 17))) { return false }

            a = parseInt(StrNo.substr(0, 1)) * 7 + parseInt(StrNo.substr(1, 1)) * 9 + parseInt(StrNo.substr(2, 1)) * 10;

            a = a + parseInt(StrNo.substr(3, 1)) * 5 + parseInt(StrNo.substr(4, 1)) * 8 + parseInt(StrNo.substr(5, 1)) * 4;

            a = a + parseInt(StrNo.substr(6, 1)) * 2 + parseInt(StrNo.substr(7, 1)) * 1 + parseInt(StrNo.substr(8, 1)) * 6;

            a = a + parseInt(StrNo.substr(9, 1)) * 3 + parseInt(StrNo.substr(10, 1)) * 7 + parseInt(StrNo.substr(11, 1)) * 9;

            a = a + parseInt(StrNo.substr(12, 1)) * 10 + parseInt(StrNo.substr(13, 1)) * 5 + parseInt(StrNo.substr(14, 1)) * 8;

            a = a + parseInt(StrNo.substr(15, 1)) * 4 + parseInt(StrNo.substr(16, 1)) * 2;

            b = a % 11;

 

            if (b == 2)    //最后一位为校验位  

            {

                c = StrNo.substr(17, 1).toUpperCase();    //转为大写X  

            }

            else {

                c = parseInt(StrNo.substr(17, 1));

            }

 

            switch (b) {

                case 0: if (c != 1) { alert("身份证好号码校验位错:最后一位应该为:1"); return false; } break;

                case 1: if (c != 0) { alert("身份证好号码校验位错:最后一位应该为:0"); return false; } break;

                case 2: if (c != "X") { alert("身份证好号码校验位错:最后一位应该为:X"); return false; } break;

                case 3: if (c != 9) { alert("身份证好号码校验位错:最后一位应该为:9"); return false; } break;

                case 4: if (c != 8) { alert("身份证好号码校验位错:最后一位应该为:8"); return false; } break;

                case 5: if (c != 7) { alert("身份证好号码校验位错:最后一位应该为:7"); return false; } break;

                case 6: if (c != 6) { alert("身份证好号码校验位错:最后一位应该为:6"); return false; } break;

                case 7: if (c != 5) { alert("身份证好号码校验位错:最后一位应该为:5"); return false; } break;

                case 8: if (c != 4) { alert("身份证好号码校验位错:最后一位应该为:4"); return false; } break;

                case 9: if (c != 3) { alert("身份证好号码校验位错:最后一位应该为:3"); return false; } break;

                case 10: if (c != 2) { alert("身份证好号码校验位错:最后一位应该为:2"); return false }

            }

        }

        else    //15位身份证号  

        {

            if (!isInteger(StrNo)) { alert("身份证号码错误,前15位不能含有英文字母！"); return false }

        }

 

 

 

        switch (StrNo.length) {

            case 15: return true;

 

            case 18: return true;

 

        }

        alert("输入的身份证号码必须为15位或者18位！");

        return false;

    }  

 

 

</script>