Problem on Firefox

Problem on Firefox

I am newbie about jquery and i have tried to make like or unlike mode for my website which was coded with php. Actually, it works very well in localhost but when i upload into ftp i saw it is not working on server with firefox but i works on internet explorer here is the my code :


<script>
$(document).ready(function()
{
  $("span.on_img").mouseover(function ()
  {
    $(this).addClass("over_img");
  });

  $("span.on_img").mouseout(function ()
  {
    $(this).removeClass("over_img");
  });
});

$(function() {
$(".love").click(function()
{
var id = $(this).attr("id");
var dataString = 'id='+ id ;
var parent = $(this);


$(this).fadeOut(300);
$.ajax({
type: "POST",
url: "ajax_love.php",
data: dataString,
cache: false,

success: function(html)
{
parent.html(html);
alert("asds");

parent.fadeIn(300);
}
});


return false;

 });
});
</script>



how can i fix it ?