Get Sharepoint site Title Using ECMA script

var siteUrl = '/ProjectTemplate';
   
function retrieveWebSite() {
    var clientContext = new SP.ClientContext(siteUrl);
    this.oWebsite = clientContext.get_web();

    clientContext.load(this.oWebsite);

    clientContext.executeQueryAsync(Function.createDelegate(this, this.onQuerySucceeded), Function.createDelegate(this, this.onQueryFailed));
}

function onQuerySucceeded(sender, args) {
    alert('Title: ' + this.oWebsite.get_title() + ' Decription: ' + this.oWebsite.get_description());
}
   
function onQueryFailed(sender, args) {
    alert('Request failed. ' + args.get_message() + '\n' + args.get_stackTrace());
}
retrieveWebSite();