Replace some text (not all) within an element
<p>I've got a jQuery date &amp; time picker where I've constrained the input to either 00:00 or 12:00 so I can make it work in a kind of half day/full day way. This means it fills the box with something like:</p>

<p><code>dd/mm/yy 12:00</code></p>

<p>I'd like to be able to get the contents of this field and put it in a new field in the style of:</p>

<p><code>dd/mm/yy PM</code></p>

<p>So, can I get the <code>.val()</code> of this text field and replace <em>just some</em> of the content of it, rather than all?</p>
