Force events from javascript

Question

i'm trying force an event from javascript.

I have a "select" element in the html and i'm forcing the value of this from javascript but this does not trigger the "change" event. How can I force the event?

HTML:

<th><select id="filtro_select_periodo"></select></th>

Javascript:

window.onload = function() { 
    let fecha = new Date();

    cargarSelectPeriodo();

    filtro_select_periodo.value = fecha.getMonth();
};

filtro_select_periodo.addEventListener("change", (e) => {
    let fecha = new Date();

    fecha = new Date(fecha.getFullYear(), e.value, fecha.getDate())

    let periodo = getFechaDesdeHasta(fecha);

    filtro_periodo_desde.value = periodo.desde;
    filtro_periodo_hasta.value = periodo.hasta;

    actulizarListado();
});

Events occur when the user will himself change the value of select. — Maheer Ali, Apr 18 '19 at 12:41
@Nof, So you want to select a value in combo box then trigger the change event on it using JS — Ganesh Patel, Apr 18 '19 at 12:43
This is the correct behavior. The `change` event is only triggered by a user's interaction. Instead of trying to trigger the event, just invoke the code that the event should invoke. — Scott Marcus, Apr 18 '19 at 12:43

score 0 · Accepted Answer · answered Apr 18 '19 at 12:44

0

Events don't apply to changes caused by JavaScript, only for user actions. Otherwise every JS check, formatter, etc. would cause an infinite loop when changing the user input and thus triggering itself again.

You should move the code from filtro_select_periodo.addEventListener("change", (e) => { [code] } to a function and call it after changing the value.

answered Apr 18 '19 at 12:44

Sebastian

2,472
1
18
31

1

Thanks, I opted for this solution, but I thought you could force the event. – Nof Apr 18 '19 at 13:50

score 0 · Answer 2 · answered Apr 18 '19 at 12:51

0

You can trigger JQuery events with JQuery's .trigger('eventname') method. Like

$(filtro_select_periodo).change(function (e) => { }); // add event listener

$(filtro_select_periodo).change(); // trigger the event in your window.onload function

See: https://api.jquery.com/change/

answered Apr 18 '19 at 12:51

mhpcc

120
1
12

Thanks! I was looking for how to force the event with native javascript – Nof Apr 18 '19 at 13:49

Force events from javascript

2 Answers2