How to change options of <select> with jQuery?

Old school of doing things by hand has always been good for me.

1. Clean the select and leave the first option:

       $('#your_select_id').find('option').remove()
       .end().append('<option value="0">Selec...</option>')
       .val('whatever');
   

2. If your data comes from a Json or whatever (just Concat the data):

       var JSONObject = JSON.parse(data);
       newOptionsSelect = '';
       for (var key in JSONObject) {
           if (JSONObject.hasOwnProperty(key)) {
               var newOptionsSelect = newOptionsSelect + '<option value="'+JSONObject[key]["value"]+'">'+JSONObject[key]["text"]+'</option>';
           }
       }
   
       $('#your_select_id').append( newOptionsSelect );
   

3. My Json Objetc:

       [{"value":1,"text":"Text 1"},{"value":2,"text":"Text 2"},{"value":3,"text":"Text 3"}]
   

This solution is ideal for working with Ajax, and answers in Json from a database.

if we update <select> constantly and we need to save previous value :

var newOptions = {
    'Option 1':'value-1',
    'Option 2':'value-2'
};

var $el = $('#select');
var prevValue = $el.val();
$el.empty();
$.each(newOptions, function(key, value) {
   $el.append($('<option></option>').attr('value', value).text(key));
   if (value === prevValue){
       $el.val(value);
   }
});
$el.trigger('change');