function authenticateUserViaEmail() {

log("authenticateUserViaEmail called");

// Initialize the Amazon Cognito credentials provider
AWS.config.region = 'us-east-1'; // Region
AWS.config.credentials = new AWS.CognitoIdentityCredentials({
    IdentityPoolId: identityPoolId,
});

AWSCognito.config.region = 'us-east-1';
AWSCognito.config.credentials = new AWS.CognitoIdentityCredentials({
    IdentityPoolId: identityPoolId,
});

var authenticationData = {
    Username : document.getElementById("email").value,
    Password : document.getElementById("password").value
};

log("using: " + JSON.stringify(authenticationData));

var authenticationDetails = new AWSCognito.CognitoIdentityServiceProvider.AuthenticationDetails(authenticationData);
var poolData = { UserPoolId : userPoolId,
    ClientId : clientId
};
var userPool = new AWSCognito.CognitoIdentityServiceProvider.CognitoUserPool(poolData);
var userData = {
    Username : document.getElementById("email").value,
    Pool : userPool
};
var cognitoUser = new AWSCognito.CognitoIdentityServiceProvider.CognitoUser(userData);

log("About to call authenticateUser...");

cognitoUser.authenticateUser(authenticationDetails, {
    onSuccess: function (result) {
        log('Access token: ' + result.getAccessToken().getJwtToken());
    },
    onFailure: function(err) {
        log(err);
        console.error(err);
    },
});
}