<div style="position:absolute;z-index:3;top:160px;left:180px;">
<img style="cursor:pointer; " src="{:U('Verify')}" onclick="this.src=this.src+'?'+Math.random()" id="safecode" style="height:50px;width:70%;"/>
</div> 
//驗證碼判斷
public function Verify(){
ob_clean();
//顯示驗證碼
$cfg=array(
'codeSet' => '0123456789', // 驗證碼字符集合
'imageH' => 25, // 驗證碼圖片高度
'imageW' => 80, // 驗證碼圖片寬度
'length' => 4, // 驗證碼位數(shù)
'fontttf' => '4.ttf', // 驗證碼字體，不設(shè)置隨機(jī)獲取
'fontSize' => 10, // 驗證碼字體大小(px)
'useNoise' => false, // 是否添加雜點
'useCurve' => false, // 是否畫混淆曲線
'bg' => array(226,229,236) //背景顏色
);
$very=new \Think\Verify($cfg);
$very->entry();
} 
//客戶端通過ajax，實現(xiàn)校驗驗證碼
public function checkVerify(){
$code = I('get.code');
$very = new \Think\Verify();
$key = $this->auth_my_code($very,$very->seKey);
// 驗證碼不能為空
$secode = session($key);
//對$code進(jìn)行加密，在比較校驗
if($this->auth_my_code($very,strtoupper($code)) == $secode['verify_code']) {
echo json_encode(array('flag'=>1,'cont'=>'驗證碼正確'));
}else{
echo json_encode(array('flag'=>2,'cont'=>'驗證碼錯誤'));
}
}
private function auth_my_code($vry,$str){
$key = substr(md5($vry->seKey), 5, 8);
$str = substr(md5($str), 8, 10);
return md5($key . $str);
}

else{
$('#safecode').attr("src","/Login/Verify?"+Math.random());
NewAlert(2,"驗證碼有誤，請重新輸入",null);
code_ok = false;
$('#verifyresult').html(msg.cont).css({'color':'red','font-size':'12px'}); 
}

<script type="text/javascript">
$("#login_btn").click(function(){
var username = $.trim($("#username").val());
var password = $.trim($("#password").val());
var code = $('#veri').val();
if(username == ""){
NewAlert(2,"請輸入用戶名",null);
shutdown();
return false;
}else if(password == ""){
NewAlert(2,"請輸入密碼",null);
shutdown();
return false;
}else if(code==''){
NewAlert(2,"請輸入驗證碼",null);
return false;
}
//ajax去服務(wù)器端校驗
$.ajax({
url:"__CONTROLLER__/checkVerify",
data:{'code':code},
dataType:'json',
success:function(msg){
if(msg.flag==1){
var data= {
username:username,
password:password
};
$.ajax({
type:"POST",
url:"{:U('Login/Login')}",
data:data,
dataType:"json",
success:function(msg){
if(msg.RespCode=='000'){
shutdown();
if(msg.org_code=='fcb'){
location.href="/Invest/index?biao_type=cwb";
}else{
location.href="{$Think.config.VIP_URL}/Individual/index";
}
}else{
NewAlert(2,msg.RespDesc,null);
return false;
}
},
error:function(){
shutdown();
},
beforeSend: function() {
Loading();
},
});
}else{
$('#safecode').attr("src","/Login/Verify?"+Math.random());
NewAlert(2,"驗證碼有誤，請重新輸入",null);
code_ok = false;
$('#verifyresult').html(msg.cont).css({'color':'red','font-size':'12px'}); 
}
}
});
}); 
</script>