Why i can't use this in header?
<p>I can't use the script in header, Here is the code: </p>

<pre><code>&lt;!DOCTYPE html&gt;
&lt;html&gt;
&lt;head&gt; 

&lt;script src="http://code.jquery.com/jquery-latest.js"&gt;&lt;/script&gt;
&lt;/head&gt;
&lt;body&gt;
 &lt;a href="javascript:void" class="sl-start"&gt;Click Here&lt;/a&gt; 
&lt;p class="slide" style="display: none"&gt;Something to display&lt;/p&gt;

&lt;script&gt;
    $(".sl-start").click(function () {
    $(".slide").show();
    });
    &lt;/script&gt;
&lt;/body&gt;
&lt;/html&gt;
</code></pre>
