[Solved- 4 Answers] how to set select element as readonly

$('#mainform').submit(function() {
    $('#formdata_container').show();
    $('#formdata').html($(this).serialize());
    return false;
});

$('#enableselect').click(function() {
    $('#mainform input[name=animal]')
        .attr("disabled", true);
    
    $('#animal-select')
        .attr('disabled', false)
    	.attr('name', 'animal');
    
    $('#enableselect').hide();
    return false;
});

#formdata_container {
    padding: 10px;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div>
    <form id="mainform">
        <select id="animal-select" disabled="true">
            <option value="cat" selected>Cat</option>
            <option value="dog">Dog</option>
            <option value="hamster">Hamster</option>
        </select>
        <input type="hidden" name="animal" value="cat"/>
        <button id="enableselect">Enable</button>
        

<select name="color">
            <option value="blue" selected>Blue</option>
            <option value="green">Green</option>
            <option value="red">Red</option>
        </select>

        <input type="submit"/>
    </form>
</div>

<div id="formdata_container" style="display:none">
    <div>Submitted data:</div>
    <div id="formdata">
    </div>
</div>

<select>
<option disabled="disabled">1</option>
<option selected="selected">2</option>
<option disabled="disabled">3</option>
</select>

jQuery('select.readonly option:not(:selected)').attr('disabled',true);

$('#selection').css('pointer-events','none');