使用JavaScript更改选项的位置

Question

我有一个包含多个选项的下拉列表，现在我想在列表顶部插入一个新选项。我该怎么做？

function insertOptionAll (DOMtarget)
{
    var option = document.createElement("option");
    option.text = "Some option";
    option.value = 0;
    option.title = "Some option";
    DOMtarget.add(option); //appends to the end
    //DOMtarget.options[DOMtarget.options.length - 1].index = 0; --> doesnt work
}

Answer 1

尝试......

DOMtarget.insertBefore(option, DOMtarget.options[0]);

请参阅：Add new <option> to all dropdown <select> tags using javascript

Answer 2

function insertOption(selectId) {
    var selectList = document.getElementById(selectId);
    var option = document.createElement("option");
    option.text = "Some option";
    option.value = 0;
    option.title = "Some option";
    selectList.insertBefore(option, selectList.options[0]);
}