Sending raw POST requests can be sometimes more convenient. Below you can see post.js original example from PhantomJS
// Example using HTTP POST operation
var page = require('webpage').create(),
server = 'http://posttestserver.com/post.php?dump',
data = 'universe=expanding&answer=42';
page.open(server, 'post', data, function (status) {
if (status !== 'success') {
console.log('Unable to post!');
} else {
console.log(page.content);
}
phantom.exit();
});