Passing in parameter from html element with jQuery

Question

I'm working with jQuery for the first time and need some help. I have html that looks like the following:

<div id='comment-8' class='comment'>
    <p>Blah blah</p>
    <div class='tools'></div>
</div>

<div id='comment-9' class='comment'>
    <p>Blah blah something else</p>
    <div class='tools'></div>
</div>

I'm trying to use jQuery to add spans to the .tools divs that call variouis functions when clicked. The functions needs to receive the id (either the entire 'comment-8' or just the '8' part) of the parent comment so I can then show a form or other information about the comment.

What I have thus far is:

<script type='text/javascript'>

    $(function() {
        var actionSpan = $('<span>[Do Something]</span>');
        actionSpan.bind('click', doSomething);

        $('.tools').append(actionSpan);
     });

     function doSomething(commentId) { alert(commentId); }

</script>

I'm stuck on how to populate the commentId parameter for doSomething. Perhaps instead of the id, I should be passing in a reference to the span that was clicked. That would probably be fine as well, but I'm unsure of how to accomplish that.

Thanks, Brian

Answer 1

Event callbacks are called with an event object as the first argument, you can't pass something else in that way. This event object has a target property that references the element it was called for, and the this variable is a reference to the element the event handler was attached to. So you could do the following:

function doSomething(event)
{
    var id = $(event.target).parents(".tools").attr("id");
    id = substring(id.indexOf("-")+1);
    alert(id);
}

...or:

function doSomething(event)
{
    var id = $(this).parents(".tools").attr("id");
    id = substring(id.indexOf("-")+1);
    alert(id);
}

Answer 2

To get from the span up to the surrounding divs, you can use <tt>parent()</tt> (if you know the exact relationship), like this: <tt>$(this).parent().attr('id')</tt>; or if the structure might be more deeply nested, you can use parents() to search up the DOM tree, like this: <tt>$(this).parents('div:eq(0)').attr('id')</tt>.

To keep my answer simple, I left off matching the class <tt>"comment"</tt> but of course you could do that if it helps narrow down the div you are searching for.