建立自訂 Google 登入按鈕

如要建立含有自訂設定的 Google 登入按鈕，請在登入頁面中新增可容納登入按鈕的元素，編寫以自訂樣式和範圍設定呼叫 signin2.render() 的函式，並納入含有查詢字串 onload=YOUR_RENDER_FUNCTION 的 https://apis.google.com/js/platform.js 指令碼。

以下是指定自訂樣式參數的 Google 登入按鈕範例：

以下 HTML、JavaScript 和 CSS 程式碼會產生上方的按鈕：

<html>
<head>
  <meta name="google-signin-client_id" content="YOUR_CLIENT_ID.apps.googleusercontent.com">
</head>
<body>
  <div id="my-signin2"></div>
  <script>
    function onSuccess(googleUser) {
      console.log('Logged in as: ' + googleUser.getBasicProfile().getName());
    }
    function onFailure(error) {
      console.log(error);
    }
    function renderButton() {
      gapi.signin2.render('my-signin2', {
        'scope': 'profile email',
        'width': 240,
        'height': 50,
        'longtitle': true,
        'theme': 'dark',
        'onsuccess': onSuccess,
        'onfailure': onFailure
      });
    }
  </script>

  <script src="https://apis.google.com/js/platform.js?onload=renderButton" async defer></script>
</body>
</html>

您也可以為自訂 Google 登入按鈕指定設定，方法是將 data- 屬性定義為具有 g-signin2 類別的 div 元素。例如：

<div class="g-signin2" data-width="300" data-height="200" data-longtitle="true">

使用自訂圖形建立按鈕

您可以建立 Google 登入按鈕，以配合網站的設計。您必須遵守品牌規範，並在按鈕中使用適當的顏色和圖示。品牌宣傳規範也提供可用於設計按鈕的圖示素材資源。您也必須確保按鈕與其他第三方登入選項一樣醒目。

以下是使用自訂圖形建立的 Google 登入按鈕範例：

以下 HTML、JavaScript 和 CSS 程式碼會產生上述按鈕：

<html>
<head>
  <link href="https://fonts.googleapis.com/css?family=Roboto" rel="stylesheet" type="text/css">
  <script src="https://apis.google.com/js/api:client.js"></script>
  <script>
  var googleUser = {};
  var startApp = function() {
    gapi.load('auth2', function(){
      // Retrieve the singleton for the GoogleAuth library and set up the client.
      auth2 = gapi.auth2.init({
        client_id: 'YOUR_CLIENT_ID.apps.googleusercontent.com',
        cookiepolicy: 'single_host_origin',
        // Request scopes in addition to 'profile' and 'email'
        //scope: 'additional_scope'
      });
      attachSignin(document.getElementById('customBtn'));
    });
  };

  function attachSignin(element) {
    console.log(element.id);
    auth2.attachClickHandler(element, {},
        function(googleUser) {
          document.getElementById('name').innerText = "Signed in: " +
              googleUser.getBasicProfile().getName();
        }, function(error) {
          alert(JSON.stringify(error, undefined, 2));
        });
  }
  </script>
  <style type="text/css">
    #customBtn {
      display: inline-block;
      background: white;
      color: #444;
      width: 190px;
      border-radius: 5px;
      border: thin solid #888;
      box-shadow: 1px 1px 1px grey;
      white-space: nowrap;
    }
    #customBtn:hover {
      cursor: pointer;
    }
    span.label {
      font-family: serif;
      font-weight: normal;
    }
    span.icon {
      background: url('/identity/sign-in/g-normal.png') transparent 5px 50% no-repeat;
      display: inline-block;
      vertical-align: middle;
      width: 42px;
      height: 42px;
    }
    span.buttonText {
      display: inline-block;
      vertical-align: middle;
      padding-left: 42px;
      padding-right: 42px;
      font-size: 14px;
      font-weight: bold;
      /* Use the Roboto font that is loaded in the <head> */
      font-family: 'Roboto', sans-serif;
    }
  </style>
  </head>
  <body>
  <!-- In the callback, you would hide the gSignInWrapper element on a
  successful sign in -->
  <div id="gSignInWrapper">
    <span class="label">Sign in with:</span>
    <div id="customBtn" class="customGPlusSignIn">
      <span class="icon"></span>
      <span class="buttonText">Google</span>
    </div>
  </div>
  <div id="name"></div>
  <script>startApp();</script>
</body>
</html>