capture.js

var page = require('webpage').create();

if (phantom.args.length !== 5) {
    console.log('Usage: rasterize.js URL filename width height delay');
    phantom.exit();
} else {
    var address = phantom.args[0],
        output = phantom.args[1],
        width = parseInt(phantom.args[2]),
        height = parseInt(phantom.args[3]),
        delay = parseInt(phantom.args[4]);
    page.viewportSize = { width: width, height: height };
    page.clipRect = { width: width, height: height };
    page.open(address, function (status) {
        if (status !== 'success') {
            console.log('Unable to load the address!');
        } else {
            page.evaluate(function() {
                document.body.bgColor = 'white';
                document.querySelector("#prompt-modal").style.display = "none";
            });
            window.setTimeout(function () {
                page.render(output);
                phantom.exit();
            }, delay*1000);
        }
    });
}