頁面：
效果為輸入身份證號，焦掉移開後自動驗證，並返回資訊！

    <input type="text" class="reg_txt" value="身份證號" titles="請輸入您的身份證號！" name="userid" id="username" maxlength="40" onfocus="if(this.value=='身份證號'){this.value='';}" onblur="if(this.value==''){this.value='身份證號';}nunber(this.value);" style="border: 1px solid red;"
 
><br> 
    <span class="c_red" id="span_username"></span> 

JS：

    function nunber(allowancePersonValue){ 
     if(allowancePersonValue=="身份證號"){ 
      $("#span_username").show(); 
      $("#span_username").html("身份證號不能為空"); 
      return false; 
     } 
     //校驗長度，型別 
     else
 
 if(isCardNo(allowancePersonValue) === false) 
     { 
    $("#span_username").show(); 
      $("#span_username").html("您輸入的身份證號碼不正確，請重新輸入"); 
      return false; 
     } 
     //檢查省份 
     else if(checkProvince(allowancePersonValue) === false) 
     { 
      $("#span_username").show(); 
      $("#span_username"
 
).html("您輸入的身份證號碼不正確,請重新輸入"); 
      return false; 
     } 
     //校驗生日 
     else if(checkBirthday(allowancePersonValue) === false) 
     { 
      $("#span_username").show(); 
      $("#span_username").html("您輸入的身份證號碼生日不正確,請重新輸入"); 
      return false; 
     } 
     //檢驗位的檢測 
     else if(checkParity(allowancePersonValue) === false) 
     { 
      $("#span_username").show(); 
      $("#span_username").html("您的身份證校驗位不正確,請重新輸入"); 
      return false; 
     }else{ 
      $("#span_username").hide(); 
      return true; 
     } 

    } 

    //身份證省的編碼 
    var vcity={ 11:"北京",12:"天津",13:"河北",14:"山西",15:"內蒙古", 
            21:"遼寧",22:"吉林",23:"黑龍江",31:"上海",32:"江蘇", 
            33:"浙江",34:"安徽",35:"福建",36:"江西",37:"山東",41:"河南", 
            42:"湖北",43:"湖南",44:"廣東",45:"廣西",46:"海南",50:"重慶", 
            51:"四川",52:"貴州",53:"雲南",54:"西藏",61:"陝西",62:"甘肅", 
            63:"青海",64:"寧夏",65:"新疆",71:"臺灣",81:"香港",82:"澳門",91:"國外" 
           }; 

    //檢查號碼是否符合規範，包括長度，型別 
    function isCardNo(card){ 
     //身份證號碼為15位或者18位，15位時全為數字，18位前17位為數字，最後一位是校驗位，可能為數字或字元X 
     var reg = /(^\d{15}$)|(^\d{17}(\d|X)$)/; 
     if(reg.test(card) === false){ 
      //alert("demo"); 
      return false; 
     } 
     return true; 
    } 

    //取身份證前兩位,校驗省份 
    function checkProvince(card){ 
     var province = card.substr(0,2); 
     if(vcity[province] == undefined){ 
      return false; 
     } 
     return true; 
    } 

    //檢查生日是否正確 
    function checkBirthday(card){ 
     var len = card.length; 
     //身份證15位時，次序為省（3位）市（3位）年（2位）月（2位）日（2位）校驗位（3位），皆為數字 
     if(len == '15'){  
         var re_fifteen = /^(\d{6})(\d{2})(\d{2})(\d{2})(\d{3})$/; 
         var arr_data = card.match(re_fifteen); 
         var year = arr_data[2]; 
         var month = arr_data[3]; 
         var day = arr_data[4]; 
         var birthday = new Date('19'+year+'/'+month+'/'+day); 
         return verifyBirthday('19'+year,month,day,birthday); 
     } 
     //身份證18位時，次序為省（3位）市（3位）年（4位）月（2位）日（2位）校驗位（4位），校驗位末尾可能為X 
     if(len == '18'){ 
         var re_eighteen = /^(\d{6})(\d{4})(\d{2})(\d{2})(\d{3})([0-9]|X)$/; 
         var arr_data = card.match(re_eighteen); 
         var year = arr_data[2]; 
         var month = arr_data[3]; 
         var day = arr_data[4]; 
         var birthday = new Date(year+'/'+month+'/'+day); 
         return verifyBirthday(year,month,day,birthday); 
     } 
     return false; 
    } 

    //校驗日期 
    function verifyBirthday(year,month,day,birthday){ 
     var now = new Date(); 
     var now_year = now.getFullYear(); 
     //年月日是否合理 
     if(birthday.getFullYear() == year && (birthday.getMonth() + 1) == month && birthday.getDate() == day) 
     { 
         //判斷年份的範圍（3歲到100歲之間) 
         var time = now_year - year; 
         if(time >= 3 && time <= 100) 
         { 
             return true; 
         } 
         return false; 
     } 
     return false; 
    } 

    //校驗位的檢測 
    function checkParity(card){ 
     //15位轉18位 
     card = changeFivteenToEighteen(card); 
     var len = card.length; 
     if(len == '18'){ 
         var arrInt = new Array(7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2); 
         var arrCh = new Array('1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2'); 
         var cardTemp = 0, i, valnum; 
         for(i = 0; i < 17; i ++) 
         { 
             cardTemp += card.substr(i, 1) * arrInt[i]; 
         } 
         valnum = arrCh[cardTemp % 11]; 
         if (valnum == card.substr(17, 1)) 
         { 
             return true; 
         } 
         return false; 
     } 
     return false; 
    } 

    //15位轉18位身份證號 
    function changeFivteenToEighteen(card){ 
     if(card.length == '15') 
     { 
         var arrInt = new Array(7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2); 
         var arrCh = new Array('1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2'); 
         var cardTemp = 0, i;   
         card = card.substr(0, 6) + '19' + card.substr(6, card.length - 6); 
         for(i = 0; i < 17; i ++) 
         { 
             cardTemp += card.substr(i, 1) * arrInt[i]; 
         } 
         card += arrCh[cardTemp % 11]; 
         return card; 
     } 
     return card; 
    }