How do I convert this code to JQuery
<p>I've been trying to convert this code to jQuery from Javascript but to no avail. This code is for adding a new item to a list which I took from the <a href="http://msdn.microsoft.com/en-us/library/hh185011%28v=office.14%29.aspx" rel="nofollow">msdn</a> website. 
It works in javascript but I need it to run every time the page is loaded. I tried to google for why it wasn't working with javascript and found <a href="http://sharepoint.stackexchange.com/questions/28534/javascript-to-display-sharepoint-list-items-on-page-load?rq=1">this</a>. The guy who asked the question said it worked well with jQuery. So, I've been trying to convert this.
All help is appreciated! Thanks!! 
<br/>Note: As I'm working for a client, I'm not allowed to use third party tools like SPServices.</p>

<p>Edit: Code I've done till now:
    </p>

<p></p>

<p>function createListItem() {</p>

<pre><code>var clientContext = new SP.ClientContext(siteUrl);
var oList = clientContext.get_web().get_lists().getByTitle("Announcements");

var itemCreateInfo = new SP.ListItemCreationInformation();
this.oListItem = oList.addItem(itemCreateInfo);

oListItem.set_item("Title", "My New Item!");
oListItem.set_item("Body", "Hello World!");

oListItem.update();

clientContext.load(oListItem);

clientContext.executeQueryAsync(Function.createDelegate(this, this.onQuerySucceeded), Function.createDelegate(this, this.onQueryFailed));
</code></pre>

<p>}</p>

<p>function onQuerySucceeded() {</p>

<pre><code>alert("Item created: " + oListItem.get_id());
</code></pre>

<p>}</p>

<p>function onQueryFailed(sender, args) {</p>

<pre><code>alert("Request failed. " + args.get_message() + "\n" + args.get_stackTrace());
</code></pre>

<p>}
$(document).ready(function()
{
createListItem();
});</p>
