jquery get or post methods for drupal block module
For using get data by jquery ajax you need first seta menu link for listen to your ajax requst, and in callback of your menu you passed back a block or any data you want.

function yourmodule_menu () {
   $items=array();
   $items['youruniqepath'] =array(
        'title' =&gt; 'my menu',
        'description' =&gt; 'A menu link to handle ajax request',
        'page callback' =&gt; 'yourhandlerfunction',
        'access callback' =&gt; TRUE, //you can set it with your permission
      );
   return $items;
   }


and in yourhalderjust need pass a block :

function yourhandlerfunction () {
  //with any method you want get your block,
  // I suggest something like this
    $block = module_invoke('module_name', 'block_view', 'block_delta');
    print render($block);
}


and in your clientside get it with something like this

$.ajax({
    type: "POST",
    url: 'youruniqepath',
    //data: {}, you can also pass block name and act more dynamicly
    success: function (data){
        $('#yourplace').html(data);
    }
});