Google Chrome change event in input is not fired i

问题:

$('input#not-gonna-work').bind({
    keyup: function(){
        console.log('Typed a key');
        $(this).val($(this).val() + '.');// try with any other char
    },
    change: function(){
       console.log('I\'m a changed input');
    }
});

I staged this bug in this simplified jsfiddle example. My problem related to this bug is that I have a financial app that I'm building and I need to display a "Save changes" button if input data is changed. Since I need to insert thousand separator immediately on keyup (if needed) this bug really annoys me and breakes that functionality.

To reproduce it go to jsfiddle example, open console in chrome type anything in first input, keyup event will be properly fired, than un-focus input with tab or clicking outside of it and change event won't be fired. Do the same with other input and change will be fired.

I tested this in Firefox and it works as expected.

Version of Chromium that I'm using is 14.0.835.202 (Developer Build 103287 Linux) Ubuntu 11.10

and

Tried with Google Chrome 15.0.874.106 freshly installed straight from Chrome website.

I could insert separators on change event, but since users will be entering lots of 7+ digits numbers it would much better UX to have separators inserted as they type.

回答1:

I tried it in IE9 and it has the same behavior as Chrome.

I don't think it's a bug.

Using .val(value) on an HTML element will reset the "manually changed" flag and thus no change event will occur (because the user doesn't change anything manually AFTER the val() operation).

回答2:

This looks like a valid Chrome bug. My guess is that changing the value resets whatever Chrome relies on to trigger the onChange event since the user last focused on the input. I would suggest using a workaround (unfortunately) that should work in all browsers.

I've updated your code with such an example here. The idea is that you store the original value when the input receives focus, then compare the original value to the updated value when the input is blurred. If it is a different value, then perform the same logic that you would have put into your change callback.

回答3:

It seems this behavior is expected. (See http://dev.w3.org/html5/spec/common-input-element-apis.html#event-input-change).

It mentions that if you programmatically change the value, you have to manually fire the event.

And according to https://developer.mozilla.org/en-US/docs/DOM/element.onchange, Mozilla implements change as follows:

  control.onfocus = focus;
  control.onblur = blur;
  function focus () {
      original_value = control.value;
  }

  function blur () {
      if (control.value != original_value)
        control.onchange();
  }

For now, you can capture the blur event and fire 'change' event from there. (You may want check your before and after values before calling change() as done by Mozilla.)

blur: function(){
   $(this).change();
}

回答4:

That seems to be the behavior to me.. If the value of an element is changed via script then your onchange will not be triggered. In such cases you need to save the value onfocus and check the value onblur and trigger onchange manually.

See below,

DEMO: http://jsfiddle.net/vCxme/6/

$('input#not-gonna-work').bind({
    keyup: function(){
        console.log('Typed a key');
        $(this).val($(this).val() + '.');
    },
    change: function(){
       console.log('I\'m a changed input');
    },
    focus: function ( ){
        $(this).data('orig_value', $(this).val());
    },
    blur: function () {
        if ($(this).val() != $(this).data('orig_value')){
            $(this).change();
        }
    }
});
$('input#gonna-work').bind({
    keyup: function(){
        console.log('Typed a key');
    },
    change: function(){
       console.log('I\'m a changed input');
    }
});

The above implementation is from pseudo code as from FF onChange

Note: The browser change event will not be triggered when the value is changed via script.

回答5:

I would approach from a slightly different angle (so work around), of checking the value of the field every time a keyup event is performed. See http://jsfiddle.net/vCxme/3/