You can remove the existing options by using the empty method, and then add your new options:
var option = $('<option></option>').attr("value", "option value").text("Text");
$("#selectId").empty().append(option);
If you have your new options in an object you can:
var newOptions = {"Option 1": "value1",
"Option 2": "value2",
"Option 3": "value3"
};
var $el = $("#selectId");
$el.empty(); // remove old options
$.each(newOptions, function(key,value) {
$el.append($("<option></option>")
.attr("value", value).text(key));
});
Edit: For removing the all the options but the first, you can use the :gt selector, to get all the option elements with index greater than zero and remove them:
$('#selectId option:gt(0)').remove(); // remove all options, but not the first
삭제하기
$('#selectId option:gt(0)').remove();
[추가 사항] Multi-Select Combo box (왼쪽,오른쪽 이동하는 셀렉트 박스)