.
<script type="text/javascript">
(function() {
var po = document.createElement('script');
po.type = 'text/javascript'; po.async = true;
po.src = 'https://apis.google.com/js/client:plusone.js?onload=render';
var s = document.getElementsByTagName('script')[0];
s.parentNode.insertBefore(po, s);
})();
function render() {
gapi.signin.render('customBtn', {
'callback': 'signinCallback',
'clientid': 'xxxxxxxxxx.apps.googleusercontent.com',
'cookiepolicy': 'single_host_origin',
'scope': 'https://www.googleapis.com/auth/plus.login'
});
}
function signinCallback(authResult) {
}
</script>
<div id="customBtn" class="customGPlusSignIn">
<span class="icon"></span>
<span class="buttonText">Google</span>
</div>