jQuery로 선택된 값 읽기
$("#select_box option:selected").val();
$("select[name=name]").val();

jQuery로 선택된 내용 읽기
$("#select_box option:selected").text();

선택된 위치
var index = $("#test option").index($("#test option:selected")); 

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// Add options to the end of a select
$("#myselect").append("<option value='1'>Apples</option>");
$("#myselect").append("<option value='2'>After Apples</option>");

// Add options to the start of a select
$("#myselect").prepend("<option value='0'>Before Apples</option>");

// Replace all the options with new options
$("#myselect").html("<option value='1'>Some oranges</option><option value='2'>More Oranges</option><option value='3'>Even more oranges</option>");

// Replace items at a certain index
$("#myselect option:eq(1)").replaceWith("<option value='2'>Some apples</option>");
$("#myselect option:eq(2)").replaceWith("<option value='3'>Some bananas</option>");

// Set the element at index 2 to be selected
$("#myselect option:eq(2)").attr("selected", "selected");

// Set the selected element by text
$("#myselect").val("Some oranges").attr("selected", "selected");

// Set the selected element by value
$("#myselect").val("2");

// Remove an item at a particular index
$("#myselect option:eq(0)").remove();

// Remove first item
$("#myselect option:first").remove();

// Remove last item
$("#myselect option:last").remove();

// Get the text of the selected item
alert($("#myselect option:selected").text());

// Get the value of the selected item
alert($("#myselect option:selected").val());

// Get the index of the selected item
alert($("#myselect option").index($("#myselect option:selected")));

// Alternative way to get the selected item
alert($("#myselect option:selected").prevAll().size());

// Insert an item in after a particular position
$("#myselect option:eq(0)").after("<option value='4'>Some pears</option>");

// Insert an item in before a particular position
$("#myselect option:eq(3)").before("<option value='5'>Some apricots</option>");

// Getting values when item is selected
$("#myselect").change(function() {
alert($(this).val());
alert($(this).children("option:selected").text());
});