How to change the value of the currently selected item in the list box?

问题

I know one can get the value of the currently selected item like this:

var myListBoxItemText = $('#myListBox').val().toString();

But how do you change this value in the list box to something else?

回答1:

Seeing your update in the comments, here's an updated answer. Just use the :selected selector to filter the options inside of your select element to get the selected option.

To change a select element's selected option's value property:

 $('#myListBox option:selected').val('new value');

To change its display text:

 $('#myListBox option:selected').text('new text');

JSFiddle

回答2:

$("#myListBox").val("This is the new value");

Although, by 'listbox', I assume you mean a select element. In which case you'll have to add the property selected to one of the child option elements.

回答3:

$('#myListBox').val(your_val);

Here your_val denotes the value attribute of <option>

Or you can also use

$('#myListBox')[0].selectedIndex = 1;

or

  $('#myListBox').prop('selectedIndex', 1);

DEMO

DEMO 2

来源：https://stackoverflow.com/questions/10939731/how-to-change-the-value-of-the-currently-selected-item-in-the-list-box