Javascript sort select options 的方法

比較快又簡單的方式是透過 jQuery, 這幾行就搞定:

var my_options = $("#my_select option");

my_options.sort(function(a,b) {
    if (a.text > b.text) return 1;
    else if (a.text < b.text) return -1;
    else return 0
})

$("#my_select").empty().append( my_options );

也可以透過簡單的 Javascript 例如:

function sortSelect(selElem) {
        var tmpAry = new Array();
        for (var i=0;i<selElem.options.length;i++) {
            tmpAry[i] = new Array();
            tmpAry[i][0] = selElem.options[i].text;
            tmpAry[i][1] = selElem.options[i].value;
        }
        tmpAry.sort();
        while (selElem.options.length > 0) {
            selElem.options[0] = null;
        }
        for (var i=0;i<tmpAry.length;i++) {
            var op = new Option(tmpAry[i][0], tmpAry[i][1]);
            selElem.options[i] = op;
        }
        return;
    }

附註: 這個 script 沒有考慮到已經 selected 的項目的問題.

或

function sortSelect(selectToSort) {
    var arrOptions = [];

    for (var i = 0; i < selectToSort.options.length; i++)  {
        arrOptions[i] = [];
        arrOptions[i][0] = selectToSort.options[i].value;
        arrOptions[i][1] = selectToSort.options[i].text;
        arrOptions[i][2] = selectToSort.options[i].selected;
    }

    arrOptions.sort();

    for (var i = 0; i < selectToSort.options.length; i++)  {
        selectToSort.options[i].value = arrOptions[i][0];
        selectToSort.options[i].text = arrOptions[i][1];
        selectToSort.options[i].selected = arrOptions[i][2];
    }
}

資料來源:
What is the most efficient way to sort an Html Select's Options by value, while preserving the currently selected item?
http://stackoverflow.com/questions/45888/what-is-the-most-efficient-way-to-sort-an-html-selects-options-by-value-while

Javascript to sort contents of select element
http://stackoverflow.com/questions/278089/javascript-to-sort-contents-of-select-element