third_party/web_platform_tests/webdriver/modal/res/alerts.html

<html>
<!-- Padding to account for small screens of mobile devices -->
<style>
    p {margin-top:48px;}
</style>
<head>
    <title>Testing Alerts</title>

    <script type="text/javascript">
        function setInnerText(id, value) {
          document.getElementById(id).innerHTML = '<p>' + value + '</p>';
        }

        function displayPrompt() {
          setInnerText('text', prompt('Enter something'));
        }

        function displayPromptWithDefault() {
          setInnerText('text', prompt('Enter something', 'This is a default value'));
        }

        function displayTwoPrompts() {
          setInnerText('text1', prompt('First'));
          setInnerText('text2', prompt('Second'));
        }

        function displayConfirm() {
          setInnerText('text', confirm('cheese'));
        }
    </script>
</head>
<body>

<h1>Testing Alerts and Stuff</h1>

<p>This tests alerts: <a href="#" id="alert" onclick="alert('cheese');">click me</a></p>

<p>This tests alerts: <a href="#" id="empty-alert" onclick="alert('');">click me</a></p>

<p>Let's make the <a href="#" id="prompt" onclick="displayPrompt();">prompt happen</a></p>

<p>Let's make the <a href="#" id="prompt-with-default" onclick="displayPromptWithDefault();">prompt with default happen</a></p>

<p>Let's make TWO <a href="#" id="double-prompt" onclick="displayTwoPrompts();">prompts happen</a></p>

<p>This tests confirm: <a href="#" id="confirm" onclick="displayConfirm();">test confirm</a></p>

<div id="text"></div>
<div id="text1"></div>
<div id="text2"></div>

</body>
</html>