jQuery change() on <select> and firefox

问题:

I have a dropdown that triggers an ajax call when its changed:

$('.travel-to').change(function(){  
    $.ajax({
        type: "GET",
        url: "/inc/rates/rates-viewer.php",
        data: "shtech=y&c_name="+escape($(this).val()),
        success: function(html){
            $(".rates-viewer").html(html);
            $(".rates-viewer tr.numbers td").css({ opacity: 0 }).fadeTo("slow",1);
        }
    });
});

My problem is, in Firefox, using the up/down cursor keys to cycle through the dropdown options, doesn't trigger the js onChange() event. It's ok in IE.

How can I make Firefox see the up/down cursors as an onChange? Can I do an either/or on the event, to make either an onChange or a keypress trigger the same thing?

Thanks.

回答1:

You're actually taking advantage of a bug in IE. Firefox supports onChange correctly, as it's not supposed to fire until the browser loses focus of the select field. (I answered a question yesterday about this very issue, in fact.) It's actually kind of dangerous to use onChange with a select, especially because there's no way for keyboard only users to skip some options. (On top of that, the mouse wheel seems to spin by multiple answers, but it actually fires onChange for each entry it passes by on IE.)

If you really want the event to fire whenever someone presses up or down, I would hook into the onKeyPress or onKeyDown events to fire whenever the "up" or "down" key is pressed.

回答2:

better option is use .on() to bind function as multiple events

$("#member").on("change keyup", function(){
    -----
});

回答3:

Maybe instead of using the change() event use the blur() event and check to see if the value changed?

FYI, i have not tested this, just an idea that I had. and I am not sure if this is the desired effect because it would trigger on a lost of focus, but I am suggesting it as to keep the effect consistent across different browsers.

var currentValue;

$('.travel-to').blur(function(){
    var val = $(this).val();
    if (currentValue != val) {
        currentValue = val;
        $.ajax({
            type: "GET",
            url: "/inc/rates/rates-viewer.php",
            data: "shtech=y&c_name="+escape(currentValue),
            success: function(html){
                $(".rates-viewer").html(html);
                $(".rates-viewer tr.numbers td").css({ opacity: 0 }).fadeTo("slow",1);
            }
        });
    }
});

回答4:

I've just experienced some weird behavior in firefox which enables the user to open the select dropdown, navigate with the arrows and then instead of tabbing out or clicking on a side the user can click another element which will result into changing the select value without firing change event.

To work around this you can trigger the change whenever the keyup (please also suggest other events?) event is fired and the select has a different value then the previous.

var selectRegistry = {},
    $selects = $('select');

$selects.bind('change', function() {
    var $this = $(this);
    selectRegistry[$this.attr('id')] = $this.val();
});

$selects.bind('keyup scroll select', function() {
    var $this = $(this);
    if ($this.val()!=selectRegistry[$this.attr('id')])
    {
        $this.trigger('change');
    }
});

You can use .live() function if you'll have dinamically created select elements along the runtime of the web page.

回答5:

I got it working using jquery focusout

http://api.jquery.com/focusout/