Add and Remove Options in Select using jQuery

add-option-to-dropdown.js

$("#selectBox").append('<option value="option6">option6</option>');

add-options-from-array.js

$.each(selectValues, function(key, value) {
     $('#mySelect')
         .append($("<option></option>")
         .attr("value",key)
         .text(value));
});

example-select-dropdown.html

<select id="selectBox" name="selectBox">
    <option value="option1"> option1 </option>
    <option value="option2"> option2 </option>
    <option value="option3"> option3 </option>
    <option value="option4"> option4 </option>
</select>

remove-all-options-except-first-option.js

$('select').children('option:not(:first)').remove();

remove-option-from-dropdown.js

$("#selectBox option[value='option1']").remove();