addoption.js

function createElement(tag) {
    return document.createElement(tag);
}

var addOption = function (combo, text, value) {
    /* Note by jdopazo:
     Lazy initialization for the function _add()
     I create a <select> element that I never attach to the dom
     and try to attach an <'option'> element to it with try...catch
     This way I avoid using try...catch every time this function is called */
    var testSelect = createElement('select'),
        testOption = createElement('option'),
        standards = false;
    try {
        testSelect.add(testOption, null); //standards compliant
        standards = true;
    } catch (ex) {
        testSelect.add(testOption); // IE only
    }
    if (standards) {
        addOption = function (combo, text, value) {
            var newOption = createElement('option');
            newOption.text = text;
            if (value) {
                newOption.value = value;
            }
            combo.add(newOption, null);
        };
    } else {
        addOption = function (combo, text, value) {
            var newOption = createElement('option');
            newOption.text = text;
            if (value) {
                newOption.value = value;
            }
            combo.add(newOption);
        };
    }
    addOption(combo, text, value);
}