Onchange JavascripT Doesn't work as expected. Javascript change event handler or source select onchange event call

jQuery .change() method binds JavaScript event handler "change"(element change), or fires this event on the selected element. The method is used with HTML form elements.

Event "select" Fires when the value of a form element changes (elements , and elements ). Please note that for elements such as radio buttons, checkboxes and drop-down list elements, the event "select" called immediately after the user makes a selection, and for elements with text content is delayed until the control loses focus (for example, elements with text type type = "text" , or ).

If the value of an element is changed using JavaScript, for example using jQuery method.val() , then the event "change" not called.

Please note that the .change() method used in conjunction with the function passed as a parameter ( handler) is, short note the .on() method, and without a parameter is shorthand for the .trigger() method:

$(selector).on(" change", handler) $(selector).trigger(" change")

Becomes block .text("Something has changed") // add text content .fadeOut(750 ); // smoothly change the transparency for the element ) ); ) ); Click 1 2

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In this example, using jQuery's .change() method, when an element (button) is clicked, we fire an event "change" on the element. Any other element in this example could have been used instead of this element.

Called or tracked JavaScript event"change" (shape change event).

• version added: 1.0.change(handler(eventObject))

  handler(eventObject)

  Type: Function()

  Event handler function.

• version added: 1.4.3.change(, handler(eventObject))

  eventData

  Type: Object

  An object with data that will be passed to the handler.

  handler(eventObject)

  Type: Function()

  Event handler function

• version added: 1.0.change()

This method is short for .on("change", handler), and .trigger("change").

The change event fires when form fields change. It tracks the fields , and . For select boxes, radio buttons and checkboxes, the event fires immediately after the change, in other cases only at the moment the user moves to another element.

For example, we have the following HTML:

Option 1 Option 2 Trigger the handler

The event handler can be attached like this:

$(".target").change(function() ( alert("Handler for .change() called."); ));

Now, when we change the value of the select element, we will see a message. It will also appear if other fields are changed, but after switching to others. If the element loses focus without any changes being made, the event does not occur. In order to trigger this event yourself, just call the .change() method without arguments:

$("#other").click(function() ( $(".target").change(); ));

After executing this code, we will see the message from the previous listing. This time we will see him twice, because... We have two elements in our form.

Example: tracking changes in the select box.

change demo div ( color: red; ) Chocolate Candy Taffy Caramel Fudge Cookie $("select") .change(function () ( var str = ""; $("select option:selected").each(function() ( str += $(this).text() + " "; )); $("div").text(str); )).change();

The OnChange handler is called when any input field is changed or any button is clicked.

The Name argument contains the lowercase name of the input field or button.

Example: Procedure OnChange(Name: String); Begin // If the price or quantity fields are changed, then calculate the amount If Name="price" Or Name="cnt" Then Summa:= RoundMul(Price, Cnt, 2); // If the amount field is changed, then calculate the price. If Name="summa" Then Price:= If(Cnt=0, 0, RoundDiv(Summa, Cnt, 2)); End;

A similar effect can be achieved by using the OnPriceChange, OnCntChange, and OnSummaChange handlers.

Example: Procedure OnPriceChange; Begin Summa:= RoundMul(Price, Cnt, 2); End; Procedure OnCntChange; Begin Summa:= RoundMul(Price, Cnt, 2); End; Procedure OnSummaChange; Begin Price:= If(Cnt=0, 0, RoundDiv(Summa, Cnt, 2)); End;

This handler is convenient to use when organizing modularity, since it collects information about almost all events. For example:

Var BaseClass: Variant; Procedure OnCreate; Begin BaseDocument.Init(Self); // Create a base class and exchange references with it. Initializing the document. End; Procedure OnChange(Name: String); Begin BaseClass.OnChange(Name); // Passing events to the base class End;

Or an example of modularity using a singleton (module property on the editor's Description tab):

Procedure OnCreate; Begin BaseClass.OnCreate(Self); // Initialize the document. End; Procedure OnChange(Name: String); Begin BaseClass.OnChange(Self, Name); // Passing events to the base class. End;

Body ( display: grid; grid-template-areas: "select result"; ) select ( grid-area: select; ) .result ( grid-area: result; )

For some elements, including , the change event doesn't fire until the control loses focus. Try entering something into the field below, and then click somewhere else to trigger the event.

The compatibility table on this page is generated from structured data. If you"d like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

Different browsers do not always agree whether a change event should be fired for certain types of interaction. For example, keyboard navigation in elements never fired a change event in Gecko until the user hit Enter or switched the focus away from the (see bug 126379). Since Firefox 63 (Quantum), this behavior is consistent between all major browsers, however.