Create simple functions like
function func_for_ajax(){
wp_localize_script( 'ajax_custom_script', 'frontendajax', array( 'ajaxurl' => admin_url( 'admin-ajax.php' )));
echo "simple demo ajax";
}
Than create your ajax pass in wordpress action threw this function name directly.
jQuery.ajax({
type: "POST",
action: 'func_for_ajax',
url: 'ajaxurl',
success: function(data){
jQuery('#content2').html(data);
}
});