function isIdCardNo(num)
{
    if (isNaN(num)) {
        //alert("输入的不是数字！"); 
        return false;
    }
    var len = num.length, re; 
    if (len == 15)
      re = new RegExp(/^(\d{6})()?(\d{2})(\d{2})(\d{2})(\d{3})$/);
    else if (len == 18)
      re = new RegExp(/^(\d{6})()?(\d{4})(\d{2})(\d{2})(\d{3})(\d)$/);
    else {
        //alert("输入的数字位数不对！"); 
        return false;
    }
    var a = num.match(re);
    if (a != null)
    {
	  var birthdate={
		year:"",
		month:"",
		day:""
		};
		var D;
      if (len==15)
      {
        D = new Date("19"+a[3]+"/"+a[4]+"/"+a[5]);
        birthdate.year="19" + a[3];
        birthdate.month = a[4];
        birthdate.day = a[5];
        var B = D.getYear()==a[3]&&(D.getMonth()+1)==a[4]&&D.getDate()==a[5];
      }
      else
      {
        D= new Date(a[3]+"/"+a[4]+"/"+a[5]);
        birthdate.year="19" + a[3];
        birthdate.month = a[4];
        birthdate.day = a[5];        
        var B = D.getFullYear()==a[3]&&(D.getMonth()+1)==a[4]&&D.getDate()==a[5];
      }
      if (!B) {
        //alert("输入的身份证号 "+ a[0] +" 里出生日期不对！"); 
        return false;
      }else{
		return D;
      }

    }
    return true;
}