My ideas for a method to inject jQuery.js into a page for Selenium testing.

jGrowl_idea.js

// Sample 1
$.jGrowl("Hello world!");
// Sample 2
$.jGrowl("Stick this!", { sticky: true });
// Sample 3
$.jGrowl("A message with a header", { header: 'Important' });
// Sample 4
$.jGrowl("A message that will live a little longer.", { life: 10000 });
// Sample 5
$.jGrowl("A message with a beforeOpen callback and a different opening animation.", {
    beforeClose: function(e,m) {
        alert('About to close this notification!');
    },
    animateOpen: {
        height: 'show'
    }
});

jqueryScript.js

javascript:(function(url) {
 var s = document.createElement('script');
 s.src = url;
 (document.getElementsByTagName('head')[0] ||
  document.getElementsByTagName('body')[0]).appendChild(s);
})('http://code.jquery.com/jquery-2.0.3.js')

javascript:(function(url) {
 var s = document.createElement('script');
 s.src = url;
 (document.getElementsByTagName('head')[0] ||
  document.getElementsByTagName('body')[0]).appendChild(s);
})('https://raw.github.com/stanlemon/jGrowl/master/jquery.jgrowl.js')

queryify.js

/** dynamically load jQuery */
(function(jqueryUrl, callback) {
    if (typeof jqueryUrl != 'string') {
        jqueryUrl = 'https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js';
    }
    if (typeof jQuery == 'undefined') {
        var script = document.createElement('script');
        var head = document.getElementsByTagName('head')[0];
        var done = false;
        script.onload = script.onreadystatechange = (function() {
            if (!done && (!this.readyState || this.readyState == 'loaded' 
                    || this.readyState == 'complete')) {
                done = true;
                script.onload = script.onreadystatechange = null;
                head.removeChild(script);
                callback();
            }
        });
        script.src = jqueryUrl;
        head.appendChild(script);
    }
    else {
        callback();
    }
})(arguments[0], arguments[arguments.length - 1]);

Test.java

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.nio.charset.Charset;
import java.util.concurrent.TimeUnit;

import org.openqa.selenium.JavascriptExecutor;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.firefox.FirefoxDriver;

/**
 * An example of loading jQuery dynamically using WebDriver.
 */
public class Test {

    // its nice to keep JavaScript snippets in separate files.
    private static final String JQUERY_LOAD_SCRIPT = "resources\\jQuerify.js";

    // driver
    public static void main(String[] args) throws Exception {
        WebDriver driver = new FirefoxDriver();
        driver.get("http://www.google.com");

        String jQueryLoader = readFile(JQUERY_LOAD_SCRIPT);

        // give jQuery time to load asynchronously
        driver.manage().timeouts().setScriptTimeout(10, TimeUnit.SECONDS);
        JavascriptExecutor js = (JavascriptExecutor) driver;
        js.executeAsyncScript(jQueryLoader /*, http://localhost:8080/jquery-1.7.2.js */);

        // ready to rock
        js.executeScript(
            "jQuery(function($) { " +
                " $('input[name=\"q\"]').val('bada-bing').closest('form').submit(); " +
            " }); "
        );
    }

    // helper method
    private static String readFile(String file) throws IOException {
        Charset cs = Charset.forName("UTF-8");
        FileInputStream stream = new FileInputStream(file);
        try {
            Reader reader = new BufferedReader(new InputStreamReader(stream, cs));
            StringBuilder builder = new StringBuilder();
            char[] buffer = new char[8192];
            int read;
            while ((read = reader.read(buffer, 0, buffer.length)) > 0) {
                builder.append(buffer, 0, read);
            }
            return builder.toString();
        }
        finally {
            stream.close();
        }        
    }
}