jQuery onchange不触发

Question

$('#selectclassid').trigger("change");
    $('#selectclassid').on('change', function() {
});

I have this format for my onchange manual trigger of on change but the problem is it is not firing. I am wondering because this is the format I see in tutorials. Could there be anything wrong in the format of on change. I am hoping that it will fire on change when the page is loaded. By the way this select option is in a div that is hidden on load.But will show on button click if this event is related to the problem. Any idea is appreciated

Answer 1

Hm, you seem to be triggering the event before you attach it - try it the other way around

 $('#selectclassid').on('change', function() {
     console.log("fired")
 });

 $('#selectclassid').trigger("change");

Answer 2

https://jsfiddle.net/ce5rg9mt/

$( document ).ready(function() {




$("#selectclassid").on('change', function() {
    alert('The option with value ' + $(this).val());
});


     $( "#selectclassid" ).trigger( "change" );

});

Answer 3

Wrap your code inside of the callback function like so:

$('#selectclassid').on('change', function(){
    //code here
});

And then call the trigger afterwards:

$('#selectclassid').trigger('change');