A WebTestCase example of adding a field to a form before submitting it

<?php
//
    public void testAddHiddenFormField() throws Exception {
        HtmlPage page = loadPage("<html><body>"
            + "<form name='myform'>"
            + "<button type='submit' id='mybutton'/>"
            + "</form>"
            + "</body></html>");
        final Map nodeValues = new HashMap();
        nodeValues.put("type", "hidden");
        nodeValues.put("name", "hiddenName");
        nodeValues.put("value", "hiddenValue");
        final HtmlHiddenInput hidden = new HtmlHiddenInput(page, nodeValues);
        page.getFormByName("myform").appendChild(hidden);
        final HtmlButton button = (HtmlButton) page.getHtmlElementById("mybutton");
        page = (HtmlPage) button.click();
        assertEquals(URL_GARGOYLE + "?hiddenName=hiddenValue", page
                .getWebResponse()
                .getUrl()
                .toExternalForm());
    }