Question

I got this to run properly giving my wrapper a black bg with an opacity on it. the problem comes when i try to change the bg color to have no opacity my content seems to drop behind the bg image.

the code

<img src="bg.jpg" id="bg" alt="">
<div class="wrapper">
    <div class="main">
        <h1>Full Screen</h1>
        <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Fusce tempus, sem id feugiat lobortis, felis velit dignissim sem, et pretium orci est et magna. Nunc non massa id odio ultrices varius. Nulla consequat sollicitudin erat sed condimentum. Cras vel magna ut tellus rhoncus dictum. Nulla dictum adipiscing quam vel condimentum. Aliquam accumsan quam in libero vehicula vel sodales justo tempus. Duis mattis leo a urna feugiat eleifend. Suspendisse cursus molestie est ornare sodales. Sed justo risus, mattis a tincidunt facilisis, mattis porta tortor. Nunc ac quam justo.</p>
    </div>
</div>

the css

#bg { 
    position: fixed; top: 0; left: 0; 
}
.bgwidth {
    width: 100%;
}
.bgheight {
    height: 100%; 
}
.wrapper{
    width:960px;
    /*border-radius: 10px;
    -webkit-border-radius: 10px;
    -moz-border-radius: 10px;
    box-shadow: 0px 0px 10px #000;
    background-color:#000;
    filter: alpha(opacity=30);
    opacity: 0.3;*/
    background-color:#000;
    margin-left:auto;
    margin-right:auto;
}

the js

$(window).load(function() {    

    var theWindow        = $(window),
        $bg              = $("#bg"),
        aspectRatio      = $bg.width() / $bg.height();

    function resizeBg() {

        if ( (theWindow.width() / theWindow.height()) < aspectRatio ) {
            $bg
                .removeClass()
                .addClass('bgheight');
        } else {
            $bg
                .removeClass()
                .addClass('bgwidth');
        }

        var newWidth = theWindow.width()-$bg.width();
        var newHeight = theWindow.height()-$bg.height();
        //alert(newWidth + "-"+ newHeight);
        $bg.css("left",(newWidth/2)+"px");
        $bg.css("top",(newHeight/2)+"px");
    }

    theWindow.resize(function() {
        resizeBg();
    }).trigger("resize");

});

Answer 1

I’ve updated @deltree’s jsfiddle. http://jsfiddle.net/trickeedickee/79aXy/2/

You need to add position: relative; to your .wrapper when you remove the opacity and it will work for you.

.wrapper {
    position: relative;
    }

I hope this helps.