Submitting a jQuery ajax form with two submit buttons

Question

I have a form that looks like this:

<form action="/vote/" method="post" class="vote_form">
    <input type="hidden" name="question_id" value="10" />
    <input type="image" src="vote_down.png" class="vote_down" name="submit" value="down" />
    <input type="image" src="vote_up.png" class="vote_up" name="submit" value="up" />
</form>

When I bind to the form's submit ($("vote_form").submit()), I don't seem to have access to which image the user clicked on. So I'm trying to bind to clicking on the image itself ($(".vote_down, .vote_up").click()), which always submits the form, regardless of whether I try

• return false;
• event.stopPropogation(); or
• event.preventDefault();

because all of those are form events.

1. Should I attach my $.post() to the form.submit() event, and if so, how do I tell which input the user clicked on, or

2. Should I attach my $.post() to the image click, and if so, how do I prevent the form from submitting also.

Here is what my jQuery code looks like now:

$(".vote_up, .vote_down").click(function (event) {
    $form = $(this).parent("form");
    $.post($form.attr("action"), $form.find("input").serialize() + {
        'submit': $(this).attr("value")
    }, function (data) {
        // do something with data
    });
    return false; // <--- This doesn't prevent form from submitting; what does!?
});

Solution 1

Based on Emmett's answer, my ideal fix for this was just to kill the form's submit with Javascript itself, like this:

$(".vote_form").submit(function() { return false; });

And that totally worked.

For completeness, some of my JS code in the original post need a little love. For example, the way I was adding to the serialize function didn't seem to work. This did:

    $form.serialize() + "&submit="+ $(this).attr("value")

Here's my entire jQuery code:

$(".vote_form").submit(function() { return false; });
$(".vote_up, .vote_down").click(function(event) {
    $form = $(this).parent("form");
    $.post($form.attr("action"), $form.serialize() + "&submit="+ $(this).attr("value"), function(data) {
        // do something with response (data)
    });
});

Solution 2

Another solution is to use a hidden field, and have the onclick event update its value. This gives you access from javascript, as well as on the server where the hidden field will get posted.

Solution 3

You can trigger the form submit on the click of the images. This will work with the preventDefault().

var vote;
$(".vote_up, .vote_down").click(function(event) {
    vote = $(this).attr("class");
    $(".vote_form").trigger("submit");
});

$(".vote_form").submit(function(event) { 
    $form = $(this);
    $.post($form.attr("action"), $form.serialize() + "&submit="+ vote, function(data) {
        // do something with response (data)
    });     
    event.preventDefault();
});

Solution 4

I don't get how return false and preventDefault failed to do their job. Maybe try replacing the image buttons with linked images:

<a href="#" class="vote_down"><img src="vote_down.png"/></a>

$('#vote_form > a').click(function(e) {
    e.preventDefault();

    //one way to know which image was clicked
    alert($(this).attr('class'));

    $.post(...
});

You can always ensure that a form does not submit by binding to the submit event, e.g.:

$('#vote_form').submit(function() {
    return false;
});

View more solutions

Comments

[Ankit Shah]

Like I said in the original question, I can do this, but I still need to know what image-input the user clicked on within this function. event.target == the form, unfortunately.

[Ankit Shah]

Like I said in the question, I have done what you've suggested in the second part, but I do not have access to which input the user clicked on. Further, I do not want to switch to linked images -- while that may work with Ajax, I still want my form to work for users w/o Javascript, as it currently does (and wouldn't with plain images).

[Ankit Shah]

While I'm not convinced this is an elegant solution, it really led me to a workable fix, which is to add: $(".vote_form").submit(function() { return false; }); (I certainly don't want to add "onsubmit='return false;'" to the form since I want the form to work w/o Ajax.)

[mhenrixon]

Thanks a bunch for this. Shortened my existing attempt quite a bit!

[Bengt]

Why not avoid hardcoding "&submit=" by using $this.attr("name")?

[PaulSkinner]

@bngtlrs I'd guess because that's a function call overhead that's simply unnecessary.

[Bengt]

@PaulSkinner Yes, the function call is unnecessary here, but I would reject calling it overhead, since it will typically not be called very frequently. My bet would be that the reusability will be worth omitting possibly premature optimization.

[user1954544]

I'm using .ajaxForm(), my solution for auto send is .ajaxForm({}).submit();. Will send ajax call without submit button and on custom event.