Hello everybody I want to make a homepage with a fullscreen image on the background with a border all around.
I have been able to do it as you can see from this jsfiddle
https://jsfiddle.net/dforce/3j5uo5qo/1/
but I would like that the border shrinks when the resolution is smaller or desappear on resolution is smaller than 979px.
I use this script to make the border:
    <script>
$theBorder=35; //border around image (change top and left values of #bg accordingly)
$bg=$("#bg");
$bgimg=$("#bg #bgimg");
$preloader=$("#preloader");
//]]> 
$(window).load(function() {
    FullScreenBackground($bgimg,$bg);
    $(window).resize(function() {
        FullScreenBackground($bgimg,$bg);
    });
});
$bgimg.load(function() {
    var $this=$(this);
    FullScreenBackground($this,$bg);
    $preloader.fadeOut("fast");
    $this.delay(200).fadeIn("slow");
});
function FullScreenBackground(theItem,theContainer){
    var winWidth=$(window).width();
    var winHeight=$(window).height();
    var imageWidth=$(theItem).width();
    var imageHeight=$(theItem).height();
    var picHeight = imageHeight / imageWidth;
    var picWidth = imageWidth / imageHeight;
    if ((winHeight / winWidth) < picHeight) {
        $(theItem).css("width",winWidth);
        $(theItem).css("height",picHeight*winWidth);
    } else {
        $(theItem).css("height",winHeight);
        $(theItem).css("width",picWidth*winHeight);
    };
    $(theContainer).css("width",winWidth-($theBorder*2));
    $(theContainer).css("height",winHeight-($theBorder*2));
    $(theItem).css("margin-left",(winWidth- $(theItem).width())/2);
    $(theItem).css("margin-top",(winHeight- $(theItem).height())/2);
}
</script>
Thank you for your help!