Help with for loop and ajax call

Help with for loop and ajax call

Hi
I want to add 5 to the variable 'paramdatastart' each time the #btn is clicked. So when I click it first time the 'paramdatastart' will be 5 and next time it will be 10 and so on How do I do that?
 
This is the code

<script type="text/javascript">

$(document).ready(function(){ 
var ajax_load = "<img src='http://image.gif' alt='loading...' />"; 
var loadUrl = "/ajaxtest.jsp"; 
$("#btn").click(function() {       
for(var paramdatastart = 0;paramdatastart <= 5; paramdatastart++)
alert(paramdatastart * 5);
}
           
var paramdataend = 100;
$("#forresult").html(ajax_load);
$.ajax({
type: "POST",
cache: false,
url: loadUrl,
data:"paramdatastart=" + paramdatastart + "&paramdataend=" + paramdataend,
datatype:"html",
success: function(responseText){
$("#forresult").html(responseText); 
}
}); 
return false;
});                             
});
</script>






















html
<a id="btn">link</a>
<p id="forresult"></p>