jQuery if checkbox is checked

Question

I have a function below that I want to only trigger when a checkbox in the same tr is checked. Please tell me what I am doing wrong, the usual methods are not working. Thanks

JS

$(".add_menu_item_table").live('click', function() {
  var value_td = $(this).parents('tr').find('td.td_name').text();
  if ($('input.checkbox_check').attr(':checked')); {
    var newDiv = $('<div class="div_menu_button"></div>');
    var showDiv = $('<div id="show' + "0" + numShow++ + '" class="menu_button_info hidden"></div>');
    var toggleTrigger = $('<a id="toggleshow' + "0" + numToggle++ + '" data-target="#show' + "0" + numTarget++ + '" class="toggle_trigger actions">&nbsp;</a><div style="padding:5px"></div>');
    var menuForm = $('<form id="menu_edit_form' + "0" + numForm++ + '" class="menu_creation_form"></form>');
    $('#created_buttons_list').append(
      newDiv.text(value_td)
    );
    newDiv.wrap("<li></li>");
    newDiv.append(toggleTrigger);
    newDiv.append(showDiv);
    showDiv.append(menuForm);
    menuForm.html('<label for="navigation_label">Navigation Label</label><input id="navigation_label' + "0" + numLabelone++ + '" type="text" placeholder="Navigation Label" name="navigation_label"><label for="attribute">Attribute</label><input id="attribute' + "0" + numLabeltwo++ + '" type="text" type="text" placeholder="Attribute" name="attribute"><label for="url">URL</label><input id="url' + "0" + numLabelthree++ + '" type="text" type="text" placeholder="URL" name="url"><input type="button" value="Remove" class="button_link remove_button"> <input type="reset" value="Cancel" class="button_link">');
  }
});

var numToggle = 0;
var numShow = 0;
var numTarget = 0;
var numForm = 0;
var numLabelone = 0;
var numLabeltwo = 0;
var numLabelthree = 0;

<table width="316px" border="0" cellspacing="0" cellpadding="0" id="table-data">
  <tbody>
    <tr>
      <td width="20px"><input type="checkbox" style="width:20px;" value="1" name="checkbox"></td>
      <td width="200px"><a href="/admin/feedbackmanager/sortby/2/sortdesc/0">Page Name</a></td>
      <td width="20px"><a href="/admin/feedbackmanager/sortby/3/sortdesc/0">Add</a></td>
    </tr>
    <tr>
      <td><input type="checkbox" style="width:20px;" value="1" name="checkbox" class="checkbox_check"></td>
      <td class="td_name">Timeplot</td>
      <td><input class="add_menu_item_table" name="add_menu_item" value="Add" type="button"></td>
    </tr>
    <tr>
      <td><input type="checkbox" style="width:20px;" value="1" name="checkbox" class="checkbox_check"></td>
      <td class="td_name">Operations Manuals</td>
      <td><input class="add_menu_item_table" name="add_menu_item" value="Add" type="button"></td>
    </tr> 
  </tbody>
</table>

Answer 1

for jQuery 

if ($('input.checkbox_check').prop('checked')) {
    //blah blah
}