JQuery :: Click Function Of Anchor Tag Not Working With Href Other Than #?

I started with the simplest step - the hide() function:

$(document).ready(function(){
$("a#p").click(function(event){
$("#HiddenDiv").hide();
})
});

It worked fine as long as the href attribute of the anchor tag was '#'. Then I tried using href other than '#' and ran into a problem. I just changed the href to:

<a id="p" href="test.php">Click me</a><br />
<div id="HiddenDiv">Testing mate</div>

test.php is the page in which both these sections (html and jquery) are present, so like a postback to the same page.

This method didn't work and on clicking the anchor tag, the div stayed visible.

I then tried theevent.preventDefault(); method and that worked.

So I experimented more. I tried using the hide function on a dynamic link, something like test.php?a=1.

I ran into a problem again. The div remained visible on clicking that link.