jQuery slider left and right buttons, firefox does

Question

i made this wordpress theme that displays the loop horizontally: http://zarifnyc.com/category/news/

<Script>
var curx = $('#blog').css(''); 
if(curx <= 0) {hide('#leftbutton')} else {show('#leftbutton')}
if(curx >= 25000) {hide('#rightbutton')} else {show('#rightbutton')}

$(function() 
{
  $('#rightbutton').click(function() {
$('#blogbox').animate({"left" : '-=1070px'});
return false;
});
  $('#leftbutton').click(function() {
$('#blogbox').animate({"left" : '+=1070px'});
return false;
});
  });
</script>

...it worked until i try to add an "if" statement to hide the left button on the first post, and right on the last (or use infinite scroll).

'just started to learn jQuery, so any help would be appreciated, thanks!