IBM Worklight 6.1 - How to send post values in adapter?

I'm using IBM Worklight 6.1 for my mobile app project. How can I send post values in adapter?

function getUsername(userAlias,locale) {
    path = "rest-rib/service/Login/login_username";
    
    var input = {
        method : 'post',
        returnedContentType : 'json',
        path : path
    };
    
    
    return WL.Server.invokeHttp(input);
}

You should read about HTTP adapters.

• Training module
• Information Center (scroll down to invokeHttp)
• Sample project

More:

• IBM Worklight - Sending HTTP POST request from the client side
• how to use plain text in adapter worklight

The below simple POST example is based on this POST method example from W3C Schools.

Adapter XML:

<?xml version="1.0" encoding="UTF-8"?>

<wl:adapter name="PostExample"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xmlns:wl="http://www.worklight.com/integration"
    xmlns:http="http://www.worklight.com/integration/http">

    <displayName>PostExample</displayName>
    <description>PostExample</description>
    <connectivity>
        <connectionPolicy xsi:type="http:HTTPConnectionPolicyType">
            <protocol>http</protocol>
            <domain>www.w3schools.com</domain>
            <port>80</port> 
        </connectionPolicy>
        <loadConstraints maxConcurrentConnectionsPerNode="2" />
    </connectivity>

    <procedure name="sendParams"/>
</wl:adapter>

Adapter implementation:

function sendParams() {
    path = "tags/demo_form_method_post.asp";
    
    var input = {
        method : 'post',
        path: path,
        parameters: {fname: 'idan', lname: 'adar' } 
    };
    
    return WL.Server.invokeHttp(input);
}