jQuery selector for <select>'s <option> box

Given the HTML below, I need a jQuery selector that selects the <option> with the with-stamp class.

<select name="preset_select">
    <option selected="selected" value="original">ORIGINAL</option>
    <option value="large">LARGE</option>
    <option class="with-stamp" value="medium">MEDIUM</option>
</select>

$("select[name=preset_select]").change(function() {
    // console.log( $(this).hasClass("wit开发者_Python百科h-stamp") ); // all false
    // console.log( $("select[name=preset_select] option").hasClass("with-stamp") ); // all true
});

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$("select[name='preset_select']").change(function() {
    $(this).children(':selected').hasClass('with-timestamp')
}

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You need to check only the :selected <option> (since .hasClass() returns true if any of the elements in the set have the class), like this:

$("select[name=preset_select] option:selected").hasClass("with-stamp")

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$("select[name=preset_select] option:selected").hasClass('with-stamp').change(function() { 

});