disabled and selected is not working in customize select option menu (Javascript)

i have customized select option menu by java script but there is a problem,this code is not working when option tag is disabled or selected as true. i want this solution by javas cript.

<form class="wrapper" action="index.html">
              <ul>
                  <li>
                      <div class="magneto-combobox">
                          <select class="combo-box" data-element="combobox">
                              <option value="apple" disabled>apple</option>
                              <option value="mango">mango<option>
                              <option value="banana" >banana<option>
                          </select>
                      </div>
                  </li>
                  <lil>
                      <input type="submit" value="submit"/>
                  </lil>
              </ul>
          </form>

var select = document.getElementsByTagName('select'); var customselect = []; var menu = []; var items = []; for(var i = 0 ; i