How to add a button click event on a button that was added dynamically using jQuery?

The jQuery code that adds the dynamic buttons inside a div container:

$('#pg_menu_content').empty();

$div = $('<div data-role=fieldcontain/>');

$(<input type='button' value='Dynamic Button' id='btn_a' />).appendTo($div.clone()).appendTo('#pg_menu_content');

Question 1:
How can I add a click event for the above button? I tried the below and it has not triggered

$(#btn_a).click(function(){

  alert ('button clicked');

});

Question 2:
How can I get the value of the button inside the click event? For example I want to get the value 'Dynamic Button' inside the click event function.

Can you guys please help me on this.