thinkphp系统自带验证码

        <div class="verify_code cf g-hidden" id="J-actionupload-sheet-verifyCode">
		  <dl class="cf">
            <dt>验证码<span>*</span></dt>
            <dd><input class="textinput" name="verify_code" type="text" required><img alt="点击切换" src="{:U('verify')}"><a title="换一张" href="javascript:;">换一张</a></dd>
          </dl>
          <p class="g-validator-msg" data-validator-target="verify_code" data-validator-msg="请输入验证码"></p>
        </div>

　　验证方法：

    public function verify(){
    	$config =	array(
    			'fontSize'  =>  16,              // 验证码字体大小(px)
    			'useNoise'=>false,
    			'useCurve'=>false
    			 
    	);
    	$verify = new ThinkVerify($config);
    	$verify->entry(1);
    }

　　

        if(!$this->check_verify(trim(I('post.verify_code')))){
            $json['rst']='9';
            $this->ajaxReturn($json);
        }

    function check_verify($code, $id = 1){
        $verify = new ThinkVerify();
        return $verify->check($code, $id);
    }