Getting input checkbox control ID on aspx.cs which is inside

I have a page named request.aspx and have a script, inside script i have a input check box control i want to access same ID on the same page i.e. request.aspx.cs, i can't use runat=server since it is client side, i just wanted to get the value of the checkbox whenever it is checked or unchecked, below is the part of code

The ID I wanted to get is 'chkEmployeeOnly' and i need to check if that checkbox is checked or not,

I searched many places didn't find a way to get it.

<script type="text/template" id="menu-display-options">
  <div style="top: 0; position: absolute; z-index: 5000;">
    <ul id='mnuDisplayOptions' style='display:none;'>

      <li id='itemEmployeeOnly'>
        <input type='checkbox' name='chkEmployeeOnly' id='chkEmployeeOnly' />
        <label id='lblEmployeeOnly' for='chkEmployeeOnly'>Show Only My Schedule</label>
      </li>
    </ul>
  </div>
</script>