1:先配置服务号

2:php代码

<?php
class Saoyisao {
    private $appId;
    private $appSecret;
    public function __construct($appId, $appSecret) {
        $this->appId = $appId;
        $this->appSecret = $appSecret;
    }
    public function getSignPackage() {
        $jsapiTicket = $this->getJsApiTicket();
// 注意 URL 一定要动态获取，不能 hardcode.
        $protocol = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off' || $_SERVER['SERVER_PORT'] == 443) ? "https://" : "http://";
        $url = $protocol.$_SERVER["HTTP_HOST"].$_SERVER["REQUEST_URI"];
        $timestamp = time();
        $nonceStr = $this->createNonceStr();
// 这里参数的顺序要按照 key 值 ASCII 码升序排序
        $string = "jsapi_ticket=$jsapiTicket&noncestr=$nonceStr&timestamp=$timestamp&url=$url";
//$string = "jsapi_ticket=$jsapiTicket&noncestr=$nonceStr&timestamp=$timestamp&url=$url";
//echo $string;
        $signature = sha1($string);
        $signPackage = array(
            "appId" => $this->appId,
            "nonceStr" => $nonceStr,
            "timestamp" => $timestamp,
            "url" => $url,
            "signature" => $signature,
            "rawString" => $string
        );
        return $signPackage;
    }
    private function createNonceStr($length = 16) {
        $chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        $str = "";
        for ($i = 0; $i < $length; $i++) {
            $str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
        }
        return $str;
    }
    private function getJsApiTicket() {
        $accessToken = $this->getAccessToken();
        $url = "https://api.weixin.qq.com/cgi-bin/ticket/getticket?type=jsapi&access_token=$accessToken";
        $res = json_decode($this->httpGet($url));
        $ticket = $res->ticket;
        return $ticket;
    }
    private function getAccessToken() {
        $url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=$this->appId&secret=$this->appSecret";
        $res = json_decode($this->httpGet($url));
        $access_token = $res->access_token;
        return $access_token;
    }
    private function httpGet($url) {
        $curl = curl_init();
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($curl, CURLOPT_TIMEOUT, 500);
        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
        curl_setopt($curl, CURLOPT_URL, $url);
        $res = curl_exec($curl);
        curl_close($curl);
        return $res;
    }
}
?>

3:页面代码

 <a href="javascript:;"  id="wxcode">扫一扫</a>

<script src="https://res.wx.qq.com/open/js/jweixin-1.4.0.js"></script>

<script>
    wx.config({
// 开启调试模式,调用的所有api的返回值会在客户端alert出来，若要查看传入的参数，可以在pc端打开，参数信息会通过log打出，仅在pc端时才会打印。
        debug: false,
// 必填，公众号的唯一标识
// appId: "wx259ea197bf8b2eab",
        appId: "<?php echo $signPackage["appId"];?>",
// 必填，生成签名的时间戳
        timestamp:"<?php echo $signPackage["timestamp"];?>",
// 必填，生成签名的随机串
        nonceStr:"<?php echo $signPackage["nonceStr"];?>",
// 必填，签名，见附录1
// signature:"805c5e6f956fa5572b5b3ccc65d7581fe6cd37e1",
        signature:"<?php echo $signPackage["signature"];?>",
// 必填，需要使用的JS接口列表，所有JS接口列表见附录2
        jsApiList : [ 'scanQRCode' ]
    });

    wx.error(function(res) {
        alert("错误：" + res.errMsg);//这个地方的好处就是wx.config配置错误，会弹出窗口哪里错误，然后根据微信文档查询即可。
    });

    wx.ready(function() {
        wx.checkJsApi({
            jsApiList : ['scanQRCode'],
            success : function(res) {
            }
        });
//点击按钮扫描二维码
        $('#wxcode').click(function(){
// alert(1);
            wx.scanQRCode({
                needResult: 1, // 默认为0，扫描结果由微信处理，1则直接返回扫描结果，
                scanType: ["qrCode","barCode"], // 可以指定扫二维码还是一维码，默认二者都有
                success: function (res) {
                    var result = res.resultStr; // 当needResult 为 1 时，扫码返回的结果

                    alert(result);
                    //cardInfo(result);
                }
            });
        })
    });
</script>