jQuery Set Select Index

Question

NOTE: answer is dependent upon jQuery 1.6.1+

$('#selectBox :nth-child(4)').prop('selected', true); // To select via index
$('#selectBox option:eq(3)').prop('selected', true);  // To select via value

---

Thanks for the comment, .get won't work since it returns a DOM element, not a jQuery one. Keep in mind the .eq function can be used outside of the selector as well if you prefer.

$('#selectBox option').eq(3).prop('selected', true);

---

You can also be more terse/readable if you want to use the value, instead of relying on selecting a specific index:

$("#selectBox").val("3");

Note: .val(3) works as well for this example, but non-numeric values must be strings, so I chose a string for consistency.
(e.g. <option value="hello">Number3</option> requires you to use .val("hello"))

This may also be useful, so I thought I'd add it here.

If you would like to select a value based on the item's value and not the index of that item then you can do the following:

Your select list:

<select id="selectBox">
    <option value="A">Number 0</option>
    <option value="B">Number 1</option>
    <option value="C">Number 2</option>
    <option value="D">Number 3</option>
    <option value="E">Number 4</option>
    <option value="F">Number 5</option>
    <option value="G">Number 6</option>
    <option value="H">Number 7</option>
</select>

The jquery:

$('#selectBox option[value=C]').attr('selected', 'selected');

$('#selectBox option[value=C]').prop('selected', true);

The selected item would be "Number 2" now.

Try this instead:

$("#selectBox").val(3);

Even simpler:

$('#selectBox option')[3].selected = true;

# Set element with index
$("#select option:eq(2)").attr("selected", "selected");

# Set element by text
$("#select").val("option Text").attr("selected", "selected");

when you want to select with top ways for set selection , you can use
$('#select option').removeAttr('selected'); for remove previous selects .

# Set element by value
$("#select").val("2");

# Get selected text
$("#select").children("option:selected").text();  # use attr() for get attributes
$("#select option:selected").text(); # use attr() for get attributes 

# Get selected value
$("#select option:selected").val();
$("#select").children("option:selected").val();
$("#select option:selected").prevAll().size();
$("option:selected",this).val();

# Get selected index
$("#select option:selected").index();
$("#select option").index($("#select option:selected"));

# Select First Option
$("#select option:first");

# Select Last Item
$("#select option:last").remove();


# Replace item with new one
$("#select option:eq(1)").replaceWith("<option value='2'>new option</option>");

# Remove an item
$("#select option:eq(0)").remove();