【准备工作】
api库：https://console.developers.google.com/apis/library?
①在google的API库，找到：google+API，【创建项目】

image.png

【html部分】
 <div class="login-other" >
    <img class="btn2" id="customBtn" style="cursor:pointer;" alt="login-Google" title="Google+" src="../image/G+.png">
</div>

【js部分】
$.getScript("https://apis.google.com/js/api:client.js",function (res) {
        startApp();
    });
    var googleUser = {};
    var startApp = function () {
        gapi.load('auth2', function () {
            auth2 = gapi.auth2.init({
                //726009858027-1fuqkvl234ehdode55mhr90msp9ovuvt.apps.googleusercontent.com
                client_id: '726009858027-1fuqkvl234ehdode55mhr90msp9ovuvt.apps.googleusercontent.com', //客户端ID
                cookiepolicy: 'single_host_origin',
                scope: 'profile' //可以请求除了默认的'profile' and 'email'之外的数据
            });
            attachSignin(document.getElementById('customBtn'));

        });
    };

    function attachSignin(element) {
        auth2.attachClickHandler(element, {},
            function (googleUser) {
                var profile = auth2.currentUser.get().getBasicProfile();
                var userId = profile.getId();
                var FullName = profile.getName();
                var GivenName = profile.getGivenName();
                var FamilyName = profile.getFamilyName();
                var Email = profile.getEmail();
                var ImageURL = profile.getImageUrl();
                var data = {
                    userId: userId,
                    Headpic: ImageURL,
                    FullName: FullName,
                    GivenName: GivenName,
                    FamilyName: FamilyName,
                    Email: Email,
                    loginTye: 'google+'
                };
                if (userId > 0) {
                    $.ajax({
                        url: "index.php?route=account/login/otherLogin",//后台处理逻辑
                        data: {
                            firstname: FamilyName,
                            lastname: GivenName,
                            email: Email,
                            openid: userId,
                            loginType: data.loginTye
                        },
                        type: "post",
                        dataType: 'json',
                        success: function (data) {

                            if (data['redirect']) {
                                location = data['redirect'];
                            }
                        },
                        error: function (error) {
                            //console.log(error);
                        }
                    });
                }
                layer.msg('Login successful, page jump...', {icon: 1});
                //console.log('Successful login for: ' + JSON.stringify(data));

            },
            function (error) {
                console.log(JSON.stringify(error, undefined, 2));
            });
    }

    //注销
    function signOut() {
        var auth2 = gapi.auth2.getAuthInstance();
        auth2.signOut().then(function () {
            alert('用户注销成功');
        });
    }