Array push not working in IE5 using javascript?

Question

When I try to load the select options into the optStored array using the array push, the array always remains empty. In chrome, firefox, and safari the code is working correctly but not in Internet Explorer. Is there a work around for this or nothing can be done about this?

Updated 2:12am 10/11/16: Made some changes to the code, previous code is commented out but the array still remains empty! Is there a solution?

// array to store select options
var optStored = [];

// filter select 
function filterFruits(el) {
  var value = el.value.toLowerCase();
  var form = el.form;
  var opt, sel = form.fruits;
  if (value == "") {
    restoreOpts();
  } else {
    for (var i = sel.options.length - 1; i >= 0; i--) {
      opt = sel.options[i];
      if (opt.text.toLowerCase().indexOf(value) == -1) {
        sel.removeChild(opt);
      }
    }
  }
}

// Restore select options
function restoreOpts() {
  var sel = document.getElementById('fruits');
  sel.options.length = 0;
  for (var i = 0, iLen = optStored.length; i < iLen; i++) {
    // Recent Update 2:12am 10/11/16:
    // Found aworkaround for restoring the select options 
    // This method works with versions of IE4+
    sel.options[sel.options.length] = new Option(optStored[i].text, optStored[i].value, false, false);

    // Recent Comment Update 2:12am 10/11/16: 
    // Console complains of a type mismatch error
    // sel.add(optStored[i], null); 
  }
}

// Load select options
window.onload = function() {
  var sel = document.getElementById('fruits');
  for (var i = 0, iLen = sel.options.length; i < iLen; i++) {
    // Recent Comment Update 2:12am 10/11/16: 
    // tried this method as well but no luck. 
    // it was also mentioned in the comments below
    // the array still remains empty!
    optStored[i] = sel.options[i];

    //optStored.push(sel.options[i]);
  }
};

<form>
  <input type="text" onkeyup="filterFruits(this);" placeholder="Filter">
  <select id="fruits">
    <option value="1">Apple</option>
    <option value="2">Orange</option>
    <option value="3">Cherry</option>
    <option value="4">Banana</option>
  </select>
</form>

Answer 1

If you press F12, does it give any errors in the console? The IE console is nowhere near as good as the Chrome/Firefox developer tools, but it should display any errors.

I'm wondering about passing undefined as the second argument to the add method, according to the docs it should null to append the new option to the end of the list

before is optional and an element of the collection, or an index of type long, representing the item item should be inserted before. If this parameter is null (or the index does not exist), the new element is appended to the end of the collection.

https://developer.mozilla.org/en-US/docs/Web/API/HTMLSelectElement/add

Answer 2

According to https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/push#Browser_compatibility, IE does support the push method only as of version 5.5. Try the following instead:

window.onload = function() {
  var sel = document.getElementById('fruits');
  for (var i = 0, iLen = sel.options.length; i < iLen; i++) {
    optStored[i] = sel.options[i];
  }
};