LinkedIn Login through Javascript

Requirement- Client Id

// Initialize linkedin API
<script type="text/javascript" src="http://platform.linkedin.com/in.js">
api_key: CLIENT ID
authorize: true
scope: r_basicprofile r_emailaddress
onLoad: onLinkedInLoad
</script>
<script type="text/javascript">
// After Authentication of Account
function onLinkedInLoad() {
IN.Event.on(IN, "auth", getProfileData);
}
//After successfully Login 
function onSuccess(data) {
console.log(data);
}
// Error in API call
function onError(error) {
console.log(error);
}
// Get the needed Data
function getProfileData() {
IN.API.Raw("/people/~:(id,email-address,first-name,last-name,formatted-name)").result(onSuccess).error(onError);
}
// destroy the session of linkedin
function closeSession(){
IN.User.logout();
return true;
}
</script>
<script type="in/Login"></script>

For custom Button

<script type="text/javascript">
//Invoke login window
function liAuth(){
IN.User.authorize(function(){
callback();
});
}
</script>
<input type="button" onclick="liAuth()" value="Login"/>