As the “Next”, “Prev” links are the part of AJAX responded content, you need to use either 'live'
or 'on'
based upon the jQuery version you are using.
jQuery(document).ready(function($) {
var cadenaNext="";
var cadenaPrev='';
$('#ajax-form-next').live("submit", function(e) {
e.preventDefault();
jQuery.post(MyAjax.url, {action : 'next_posts' ,cadenaNext : $('#nextPosts').val(), cadenaPrev : $('#actualPosts').val() }, function(response) {
$('#posts_container').hide(1000);
setTimeout(function() {$('#posts_container').html(response).show(1000);}, 1000);
});
});
$('#ajax-form-prev').live("submit", function(e) {
e.preventDefault();
jQuery.post(MyAjax.url, {action : 'next_posts' ,cadenaNext : $('#prevPosts').val(), cadenaPrev : $('#actualPosts').val() }, function(response) {
$('#posts_container').hide(1000);
setTimeout(function() {$('#posts_container').html(response).show(1000);}, 1000);
});
});
});