Hide and show a text field
<p>i am a beginer to javascript.I want to show a hidden textbox on a button click.i do the bellow code, but it doesnt work.</p>

<p>What is the problem with my code?</p>

<pre><code>&lt;!DOCTYPE html&gt;
&lt;html&gt;
    &lt;head&gt;
        &lt;script type="text/javascript"&gt;
        function display() {
            var z = prompt("enter your name...");
            if(z != null) {
                document.getElementById("demo").innerHTML = "thankyou " + z + "..";
                document.getElementById("case").style.visibility = 'visible';
            } else {
                document.getElementById("demo").innerHTML = "thankyou";
            }
        }
        &lt;/script&gt;
        &lt;title&gt;&lt;/title&gt;
    &lt;/head&gt;
    &lt;body&gt;
        &lt;p id="demo"&gt;
            click on the button.....
        &lt;/p&gt;&lt;button type="button" onclick="display()"&gt;submit&lt;/button&gt;
        &lt;form&gt;
            &lt;input type="text" id="case" name="myText" style="display:none"&gt;
        &lt;/form&gt;
    &lt;/body&gt;
&lt;/html&gt;
</code></pre>
