sortDropDownListByText

HTML

<body> 
<form>
      <select name="option1" id="id_option1">
<option value="Small" selected="selected">Small</option>
<option value="Large">Large</option>
<option value="Medium">Medium</option>
<option value="XL">XL</option>
</select>
    </form>
</body>

JavaScript

function sortDropDownListByText() {
// Loop for each select element on the page.
$("select").each(function() {

    // Keep track of the selected option.
    var selectedValue = $(this).val();

    // Sort all the options by text. I could easily sort these by val.
    $(this).html($("option", $(this)).sort(function(a, b) {
        return a.text == b.text ? 0 : a.text < b.text ? -1 : 1
    }));

    // Select one option.
    $(this).val(selectedValue);
});
};