こちらと同じことを、Javascript API で実装しました。
Google でログイン を設定
こちらのページを参考にしました。
【Google】ワンタップログイン
Web ページ
index.html
<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="utf-8">
<title>
Login Test
</title>
</head>
<body>
<script src="https://accounts.google.com/gsi/client" async defer></script>
<script src="login.js"></script>
<div id="buttonDiv"></div>
<hr />
<div id="outarea_aa">outarea_aa</div>
<div id="outarea_bb">outarea_bb</div>
<div id="outarea_cc">outarea_cc</div>
<div id="outarea_dd">outarea_dd</div>
<div id="outarea_ee">outarea_ee</div>
<div id="outarea_ff">outarea_ff</div>
<div id="outarea_gg">outarea_gg</div>
<div id="outarea_hh">outarea_hh</div>
<p>Aug/15/2023 PM 13:59</p>
</body>
</html>
login.js
// -----------------------------------------------------------------------
function handleCredentialResponse(response) {
console.log("Encoded JWT ID token: " + response.credential);
}
// -----------------------------------------------------------------------
window.onload = function ()
{
document.querySelector("#outarea_aa").innerHTML
= "*** login.js *** start ***"
google.accounts.id.initialize({
client_id: "371868132900-eg26ng307au*******.apps.googleusercontent.com",
callback: handleCredentialResponse
});
google.accounts.id.renderButton(
document.getElementById("buttonDiv"),
{ theme: "outline", size: "large" } // customization attributes
);
google.accounts.id.prompt(); // also display the One Tap dialog
document.querySelector("#outarea_hh").innerHTML
= "*** login.js PM 14:16 *** end ***"
}
// -----------------------------------------------------------------------