javascript - Overlapping elements - HTML, CSS, and jQuery

Question

I have elements which are overlapping and I would like to prevent this. Here is a picture: http://grab.by/cB7t

Also, here is the CSS for those elements:

.navigationItem {
    background: #808080;
    -webkit-border-radius: 360px;
    padding: 1.0em;
    text-decoration: none;
    color: #fff;
    position: absolute;
    -webkit-box-shadow: 0px 2px 5px #909090;
    font-weight: bold;
    text-shadow: 1px 1px 2px #707070;
    font-size: 1.0em;
}

And here they are in the HTML:

<a href="#" class="navigationItem" id="nav0">play</a>
<a href="#" class="navigationItem" id="nav1">register</a>
<a href="#" class="navigationItem" id="nav2">our blog</a>
<a href="#" class="navigationItem" id="nav4">contact us</a>
<a href="#" class="navigationItem" id="nav5">about us</a>
<a href="#" class="navigationItem" id="nav6">our rules</a>`

As you can see, I am using them as simple styled links using the HTML a tag. The reason that their positions are absolute is because I am moving them using jQuery:

function moveAll() {

    for(var i = 0; i < AMOUNT; i++) {
        var random = Math.random() * 500;
        $("#nav" + i).animate({"left": random + i + "px"}, "slow");
        $("#nav" + i).animate({"top": random + i + "px"}, "slow");
    }
}

When they move, though, they sometimes overlap which is annoying. How can I prevent them from overlapping? Thank you for your efforts.

Answer 1

Removing position:absolute would render them side by side.

JSFiddle

But if the whole point is to scatter them around randomly, then you will have to keep track of positioned elements and take that into account when calculating their position. You should save each link's position and calculate every next link's position according to previous already positioned links. There's simply no other way when you want random positions and non overlapping.

Final non-overlapping solution

This is a working example of non-overlapping functionality. If you'd want your links to not even touch, you should change < to <= and > to >= in the if statement condition.

Relevant code

var positions = [];
$(".navigationItem").each(function(){
    var ctx = $(this);
    var dim = {
        width: ctx.outerWidth(),
        height: ctx.outerHeight()
    };
    var success = false;

    // repeat positioning until free space is found
    while (!success)
    {
        dim.left = parseInt(Math.random() * 300);
        dim.top = parseInt(Math.random() * 300);
        var success = true;

        // check overlapping with all previously positioned links
        $.each(positions, function(){
            if (dim.left < this.left + this.width &&
                dim.left + dim.width > this.left &&
                dim.top < this.top + this.height &&
                dim.top + dim.height > this.top)
            {
                success = false;
            }
        });
    }
    positions.push(dim);
    ctx.animate({
        left: dim.left,
        top: dim.top
    }, "slow");
});