Why does the jquery change event not trigger when I set the value of a select using val()?

Question

The logic in the change() event handler is not being run when the value is set by val(), but it does run when user selects a value with their mouse

Answer 1

If you've just added the select option to a form and you wish to trigger the change event, I've found a setTimeout is required otherwise jQuery doesn't pick up the newly added select box:

window.setTimeout(function() { jQuery('.languagedisplay').change();}, 1);

Answer 2

Adding this piece of code after the val() seems to work:

$(":input#single").trigger('change');

Answer 3

I believe you can manually trigger the change event with trigger():

$("#single").val("Single2").trigger('change');

Though why it doesn't fire automatically, I have no idea.