如何从中心动画div

Question

I am trying to animate a div tag from center. Initially I want the div tag to be none visible. when user clicks on link then this div tag should animate from its center. How can I achieve this using jquery. Here is my current code.

<a href="#" class="linkone">link one</a><br><br><br><br>
<section class="one">one</section>

here is css

.one {
        margin: 0 auto;
        width: 200px;
        height: 200px;
        border: 1px solid red;
        background: lightblue;
    }

and here is my jquery

$('a').on('click', function (e) {
    e.preventDefault();
    var w = 200; //$('.one').outerWidth();
    var h = 200; //$('.one').outerHeight();
    var x = $('.one').width() / 2;
    var y = $('.one').height() / 2;
    var startW = h - y/2;
    var startH = w - x/2;
    var endTop = y - h/2;
    var endLeft = x - w/2;

    $('.one').animate({
        opacity: 1,
        width: (w+200) + 'px',
        height: (h+200) + 'px',
        top: endTop+'px',
        left: endLeft+'px'
    }, 1000);

    console.log(endLeft);
});

Answer 1

Something like this: http://jsfiddle.net/TJNTq/

$('.linkone').on('click', function (e) {
    e.preventDefault();
    var w = 200; //$('.one').outerWidth();
    var h = 200; //$('.one').outerHeight();
    var x = $('.one').width() / 2;
    var y = $('.one').height() / 2;
    var startW = h - y/2;
    var startH = w - x/2;
    var endTop = y - h/2;
    var endLeft = x - w/2;

    $('.one').show().animate({
        opacity: 1,
        width: (w+200) + 'px',
        height: (h+200) + 'px',
        marginTop: 0 + 'px'
    }, 1000);

    console.log(endLeft);
});

note that your animations of top and left weren't doing anything because the .one div isn't positioned absolutely or relatively.