PHP验证码生成程序几种方法

$arr=array(2,3,4,5,8,1,9,7,"a","b","c","d","e","f","中","国","南","北","大","小","多","少");
$b=array_rand($arr,3);

?>

echo “code:";
foreach($b  as $key)
{
 echo $arr[$key];
}
?>

（以上语句另存为一个php文件）

header(“Content-Type:text/html;charset=utf-8");
echo $_POST["yanzhengma"];
echo $_POST["code"];
if($_POST["yanzhengma"]==$_POST["code"])
{
 echo “验证码正确";
}
else
{
 die(“");
}
?>

function UPCAbarcode($code) {
  $lw = 2; $hi = 100;
  $Lencode = array('0001101','0011001','0010011','0111101','0100011',
                   '0110001','0101111','0111011','0110111','0001011');
  $Rencode = array('1110010','1100110','1101100','1000010','1011100',
                   '1001110','1010000','1000100','1001000','1110100');
  $ends = '101'; $center = '01010';
  /* UPC-A Must be 11 digits, we compute the checksum. */
  if ( strlen($code) != 11 ) { die("UPC-A Must be 11 digits."); }
  /* Compute the EAN-13 Checksum digit */
  $ncode = '0'.$code;
  $even = 0; $odd = 0;
  for ($x=0;$x<12;$x++) {
    if ($x % 2) { $odd += $ncode[$x]; } else { $even += $ncode[$x]; }
  }
  $code.=(10 - (($odd * 3 + $even) % 10)) % 10;
  /* Create the bar encoding using a binary string */
  $bars=$ends;
  $bars.=$Lencode[$code[0]];
  for($x=1;$x<6;$x++) {
    $bars.=$Lencode[$code[$x]];
  }
  $bars.=$center;
  for($x=6;$x<12;$x++) {
    $bars.=$Rencode[$code[$x]];
  }
  $bars.=$ends;
  /* Generate the Barcode Image */
  $img = ImageCreate($lw*95+30,$hi+30);
  $fg = ImageColorAllocate($img, 0, 0, 0);
  $bg = ImageColorAllocate($img, 255, 255, 255);
  ImageFilledRectangle($img, 0, 0, $lw*95+30, $hi+30, $bg);
  $shift=10;
  for ($x=0;$x    if (($x<10) || ($x>=45 && $x<50) || ($x >=85)) { $sh=10; } else { $sh=0; }
    if ($bars[$x] == '1') { $color = $fg; } else { $color = $bg; }
    ImageFilledRectangle($img, ($x*$lw)+15,5,($x+1)*$lw+14,$hi+5+$sh,$color);
  }
  /* Add the Human Readable Label */
  ImageString($img,4,5,$hi-5,$code[0],$fg);
  for ($x=0;$x<5;$x++) {
    ImageString($img,5,$lw*(13+$x*6)+15,$hi+5,$code[$x+1],$fg);
    ImageString($img,5,$lw*(53+$x*6)+15,$hi+5,$code[$x+6],$fg);
  }
  ImageString($img,4,$lw*95+17,$hi-5,$code[11],$fg);
  /* Output the Header and Content. */
  header("Content-Type: image/png");
  ImagePNG($img);
}

UPCAbarcode('12345678901');

?>

session_start();//开启session功能
header("Cache-Control: no-cache, must-revalidate");

$im = imagecreate(60,30);//定义图片宽度和高度
$vcode=getVCode();//获取要显示的字符
$bg = imagecolorallocate($im, 255, 255, 255);//定义图片背景
$txt = imagecolorallocate($im, rand(0,255), rand(0,255), rand(0,255));//定义要显示字符的颜色
imagestring($im, 8, 0, 0, $vcode, $txt);//写入字符串到图片
header(Content-type: image/jpeg);//定义Content-type
imagejpeg($im);//以JPEG格式显示图片
$_SESSION[vcode]=$vcode;//写入SESSION
 
function getVCode(){    //随机生成用户指定个数的字符串
  $codenum=4;
  $checkcode="";
  $string="";//要显示的可选字符串，请自行定义；
  for($i=0;$i<$codenum;$i  ) {  
  $number=rand(0,2);  
  switch($number){  //根据可选字符串可灵活定义；
       case 0 : $rand_number=rand(0,10);break;   
       case 1 : $rand_number=rand(11,36);break;  
       case 2 : $rand_number=rand(37,62);break;  
  }  
  $code=substr($string,$rand_number,1);
  $checkcode=$checkcode.$code;  
  } 
  return  $checkcode;
}     
?>

//该函数用来获取验证码

function getVCode() {
        var vcode=document.getElementById('vcode');
        vcode.src = 'vcode.php?nocache='+new Date().getTime();
}

//该函数用来验证验证码
function usrVCode() {
        if(!checkLogin())return false;
        var loginvcode=document.loginform.loginvcode.value;
        var xmlhttp1=createAjax();
        var data='&loginvcode='+loginvcode;
if (xmlhttp1) {
  var state=document.getElementById('state');
          xmlhttp1.open('get',?do=vcodedo'+data,true);
  xmlhttp1.send(null);
  xmlhttp1.onreadystatechange=function() {
    if (xmlhttp1.readyState==4 && xmlhttp1.status==200) {
             setTimeout("state.style.display = 'none';",1000);
     var myres=xmlhttp1.responseText;
             var result=(myres==1)?"恭喜您,验证码输入正确!":"很抱歉,验证码输入错误!";
             if(myres==0)alert(result);
             if(myres==1)usrLogin();
            }
    else {
             state.style.display = "";
     state.style.left=(document.body.offsetWidth-350)/2;
             state.style.top=(document.body.offsetHeight-235)/2+document.body.scrollTop;
    }
          }
}
}