function showAll(){
var nodesSnapshot = document.evaluate("//select/div", document, null, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null);
for (var i = 0; i < nodesSnapshot.snapshotLength; i++) {
var nodeA = nodesSnapshot.snapshotItem(i);
var elemA = document.createElement('option');
elemA.innerHTML = nodeA.innerHTML;
nodeA.parentNode.replaceChild(elemA, nodeA);
}
}
function hideSome(){
var nodesSnapshot = document.evaluate("//select/option[text()[contains(.,'HideMe')]]", document, null, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null);
for (var i = 0; i < nodesSnapshot.snapshotLength; i++) {
var nodeA = nodesSnapshot.snapshotItem(i);
var elemA = document.createElement('div');
elemA.innerHTML = nodeA.innerHTML;
nodeA.parentNode.replaceChild(elemA, nodeA);
}
}
function hideAll(){
var nodesSnapshot = document.evaluate("//select/option", document, null, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null);
for (var i = 0; i < nodesSnapshot.snapshotLength; i++) {
var nodeA = nodesSnapshot.snapshotItem(i);
var elemA = document.createElement('div');
elemA.innerHTML = nodeA.innerHTML;
nodeA.parentNode.replaceChild(elemA, nodeA);
}
}
<button onclick="showAll();">showAll</button>
<button onclick="hideSome();">hideSome</button>
<button onclick="hideAll();">hideAll</button>
<select>
<option>HideMe</option>
<option>HideMe</option>
<option>ShowMe</option>
<option>HideMe</option>
<option>ShowMe</option>
</select>