Ajax / Jquery Dilemma

[metazoid]

function platform(a) {
$(document).ready(function(){var ajaxDelay=1000;setInterval(function(){$('#mfeed').load('feed.php?platform='+ a +'&level=you');},ajaxDelay);}); 
}

Then calling it to update via a link as such:

<a href="javascript:void(0)" onclick="platform('site')">Site</a>

The problem is that my knowledge of jquery is not that in depth and the jquery function while it fetches the page via ajax perfectly and reloads the ajax every 1 second creating a live feed when I clicked on a link to inject a new variable into the javascript function changing the output of the feed it changes but every second it switches between the old and new feeds in the ajax, also the more categories are click (i.e. onclick="platform('other')") it adds that one into the rotation of feeds that show up.

Whats suppose to happen is when you click the link the new variable is injected into the ajax request and it changes to that one and the old one discontinues. This however is not happening and I have tried many different methods to make it work. Any help in this matter would be greatly appreciated as I'm quite frankly at the end of my wits.