Checked checkboxes

HTML

<input name="checkAll" type="checkbox"> Check or unckeck all
<ul>
  <li>
    <input id="selection1" type="checkbox"> Selection 1
  </li>
  <li>
    <input id="selection2" type="checkbox"> Selection 2
  </li>
  <li>
    <input id="selection3" type="checkbox"> Selection 3
  </li>
  <li>
    <input id="selection4" type="checkbox"> Selection 4
  </li>
</ul>

CSS

ul, li { list-style-type:none; }

JavaScript

$(document).ready(function() {
// Checkbox
$('input[name="checkAll"]').click(function() {
    $("input:checkbox[id^='selection']").attr('checked', $(this).prop('checked'));
 });
});