function checkIdcard(idcard){
  var Errors=new Array("true","身份证号码位数不对!","身份证号码出生日期超出范围或含有非法字符!","身份证号码校验错误!","身份证号码中地区编码不正确!");
  var area={11:"北京",12:"天津",13:"河北",14:"山西",15:"内蒙古",21:"辽宁",22:"吉林",23:"黑龙江",31:"上海",32:"江苏",33:"浙江",34:"安徽",35:"福建",36:"江西",37:"山东",41:"河南",42:"湖北",43:"湖南",44:"广东",45:"广西",46:"海南",50:"重庆",51:"四川",52:"贵州",53:"云南",54:"西藏",61:"陕西",62:"甘肃",63:"青海",64:"宁夏",65:"新疆",71:"台湾",81:"香港",82:"澳门",91:"国外"}
  var idcard,Y,JYM;
  var S,M;
  var idcard_array = new Array();
  idcard_array = idcard.split("");
  if(idcard.length != 15 && idcard.length != 18) return Errors[1];
  //if(idcard.length != 18) return Errors[1];
  if (idcard.substr(0,6) == "000000" || idcard.substr(0,6) == "111111" || idcard.substr(0,6) == "222222" || idcard.substr(0,6) == "333333" || idcard.substr(0,6) == "444444" || idcard.substr(0,6) == "555555" || idcard.substr(0,6) == "666666" || idcard.substr(0,6) == "777777" || idcard.substr(0,6) == "888888" || idcard.substr(0,6) == "999999")  return Errors[4];
  if (idcard.substr(0,6) == "123456" || idcard.substr(0,6) == "234567" || idcard.substr(0,6) == "345678" || idcard.substr(0,6) == "456789" || idcard.substr(0,6) == "567890" || idcard.substr(0,6) == "012345" || idcard.substr(0,6) == "543210" || idcard.substr(0,6) == "432109" || idcard.substr(0,6) == "321098" || idcard.substr(0,6) == "210987" || idcard.substr(0,6) == "109876" || idcard.substr(0,6) == "098765" || idcard.substr(0,6) == "987654" || idcard.substr(0,6) == "876543" || idcard.substr(0,6) == "765432")  return Errors[4];
  if (idcard.substr(0,6) == "121212" || idcard.substr(0,6) == "131313" || idcard.substr(0,6) == "141414" || idcard.substr(0,6) == "151515" || idcard.substr(0,6) == "161616" || idcard.substr(0,6) == "171717" || idcard.substr(0,6) == "181818" || idcard.substr(0,6) == "191919" || idcard.substr(0,6) == "101010")  return Errors[4];
  if (idcard.substr(0,6) == "212121" || idcard.substr(0,6) == "232323" || idcard.substr(0,6) == "242424" || idcard.substr(0,6) == "252525" || idcard.substr(0,6) == "262626" || idcard.substr(0,6) == "272727" || idcard.substr(0,6) == "282828" || idcard.substr(0,6) == "292929" || idcard.substr(0,6) == "202020")  return Errors[4];
  if (idcard.substr(0,6) == "313131" || idcard.substr(0,6) == "323232" || idcard.substr(0,6) == "343434" || idcard.substr(0,6) == "353535" || idcard.substr(0,6) == "363636" || idcard.substr(0,6) == "373737" || idcard.substr(0,6) == "383838" || idcard.substr(0,6) == "393939" || idcard.substr(0,6) == "303030")  return Errors[4];
  if (idcard.substr(0,6) == "414141" || idcard.substr(0,6) == "424242" || idcard.substr(0,6) == "434343" || idcard.substr(0,6) == "454545" || idcard.substr(0,6) == "464646" || idcard.substr(0,6) == "474747" || idcard.substr(0,6) == "484848" || idcard.substr(0,6) == "494949" || idcard.substr(0,6) == "404040")  return Errors[4];
  if (idcard.substr(0,6) == "515151" || idcard.substr(0,6) == "525252" || idcard.substr(0,6) == "535353" || idcard.substr(0,6) == "545454" || idcard.substr(0,6) == "565656" || idcard.substr(0,6) == "575757" || idcard.substr(0,6) == "585858" || idcard.substr(0,6) == "595959" || idcard.substr(0,6) == "505050")  return Errors[4];
  if (idcard.substr(0,6) == "616161" || idcard.substr(0,6) == "626262" || idcard.substr(0,6) == "636363" || idcard.substr(0,6) == "646464" || idcard.substr(0,6) == "656565" || idcard.substr(0,6) == "676767" || idcard.substr(0,6) == "686868" || idcard.substr(0,6) == "696969" || idcard.substr(0,6) == "606060")  return Errors[4];
  if (idcard.substr(0,6) == "717171" || idcard.substr(0,6) == "727272" || idcard.substr(0,6) == "737373" || idcard.substr(0,6) == "747474" || idcard.substr(0,6) == "757575" || idcard.substr(0,6) == "767676" || idcard.substr(0,6) == "787878" || idcard.substr(0,6) == "797979" || idcard.substr(0,6) == "707070")  return Errors[4];
  if (idcard.substr(0,6) == "818181" || idcard.substr(0,6) == "828282" || idcard.substr(0,6) == "838383" || idcard.substr(0,6) == "848484" || idcard.substr(0,6) == "858585" || idcard.substr(0,6) == "868686" || idcard.substr(0,6) == "878787" || idcard.substr(0,6) == "898989" || idcard.substr(0,6) == "808080")  return Errors[4];
  if (idcard.substr(0,6) == "919191" || idcard.substr(0,6) == "929292" || idcard.substr(0,6) == "939393" || idcard.substr(0,6) == "949494" || idcard.substr(0,6) == "959595" || idcard.substr(0,6) == "969696" || idcard.substr(0,6) == "979797" || idcard.substr(0,6) == "989898" || idcard.substr(0,6) == "909090")  return Errors[4];

  if(area[parseInt(idcard.substr(0,2))]==null) return Errors[4];
  switch(idcard.length){
    case 15:
    if ((parseInt(idcard.substr(6,2))+1900) % 4 == 0 || ((parseInt(idcard.substr(6,2))+1900) % 100 == 0 && (parseInt(idcard.substr(6,2))+1900) % 4 == 0 )){
      ereg = /^[1-9][0-9]{5}[0-9]{2}((01|03|05|07|08|10|12)(0[1-9]|[1-2][0-9]|3[0-1])|(04|06|09|11)(0[1-9]|[1-2][0-9]|30)|02(0[1-9]|[1-2][0-9]))[0-9]{3}$/;//测试出生日期的合法性
    }
    else{
      ereg = /^[1-9][0-9]{5}[0-9]{2}((01|03|05|07|08|10|12)(0[1-9]|[1-2][0-9]|3[0-1])|(04|06|09|11)(0[1-9]|[1-2][0-9]|30)|02(0[1-9]|1[0-9]|2[0-8]))[0-9]{3}$/;//测试出生日期的合法性
    }
    if(ereg.test(idcard))
      return Errors[0];
    else
      return Errors[2];
    break;
    case 18:
      if ( parseInt(idcard.substr(6,4)) % 4 == 0 || (parseInt(idcard.substr(6,4)) % 100 == 0 && parseInt(idcard.substr(6,4))%4 == 0 )){
        ereg = /^[1-9][0-9]{5}19[0-9]{2}((01|03|05|07|08|10|12)(0[1-9]|[1-2][0-9]|3[0-1])|(04|06|09|11)(0[1-9]|[1-2][0-9]|30)|02(0[1-9]|[1-2][0-9]))[0-9]{3}[0-9Xx]$/;//闰年出生日期的合法性正则表达式
      }
      else{
        ereg = /^[1-9][0-9]{5}19[0-9]{2}((01|03|05|07|08|10|12)(0[1-9]|[1-2][0-9]|3[0-1])|(04|06|09|11)(0[1-9]|[1-2][0-9]|30)|02(0[1-9]|1[0-9]|2[0-8]))[0-9]{3}[0-9Xx]$/;//平年出生日期的合法性正则表达式
      }
      if(ereg.test(idcard)){
        S = (parseInt(idcard_array[0]) + parseInt(idcard_array[10])) * 7 + (parseInt(idcard_array[1]) + parseInt(idcard_array[11])) * 9 + (parseInt(idcard_array[2]) + parseInt(idcard_array[12])) * 10 + (parseInt(idcard_array[3]) + parseInt(idcard_array[13])) * 5 + (parseInt(idcard_array[4]) + parseInt(idcard_array[14])) * 8 + (parseInt(idcard_array[5]) + parseInt(idcard_array[15])) * 4 + (parseInt(idcard_array[6]) + parseInt(idcard_array[16])) * 2 + parseInt(idcard_array[7]) * 1 + parseInt(idcard_array[8]) * 6 + parseInt(idcard_array[9]) * 3 ;
        Y = S % 11;
        M = "F";
        JYM = "10X98765432";
        M = JYM.substr(Y,1);
        if(M == idcard_array[17])
          return Errors[0];
        else
          return Errors[3];
      }
      else
        return Errors[2];
      break;
  default:
    return Errors[1];
    break;
  }
}

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>身份证号码js验证</title>
<script type="text/javascript" src="check_certnumber.js"></script>
<script type="text/javascript">
////身份证号码验证
  function v_cert_number(theForm){    
      var check_result = checkIdcard(theForm.cardid.value);
      if (check_result != "true"){
        document.getElementById("cert_number_div").style.color="#ff0000";
        document.getElementById("cert_number_div").innerHTML ="<image src='images/Img227876837.gif'>&nbsp;"+check_result;
        return false;  
      }    
      document.getElementById("cert_number_div").innerHTML ="<image src='images/Img227876838.gif'>身份证号码正确，需要人工验证身份号和姓名是否相符！";
  }  

////
</script>
<script>
    function validateform()
    {    
      var check_result = checkIdcard(reg.cardid.value);
      if (check_result != "true"){
          window.alert (check_result)
          reg.cardid.focus()
          return false;
         }
     }
</script>
</head>

<body>
<form action="real.php?type=upinfo" method="post"  name="reg" onSubmit="return validateform();">
<INPUT onblur=javascript:v_cert_number(document.reg) name=cardid>
<DIV class=f1 id=cert_number_div align=left>请如实填写身份证号，作为实名认证的主要依据，如果末位字符是X，则必须输入大写X</DIV>
</form>
</body>
</html>