How to fade changing background image

I want to fade the images when I do this code:

$("#large-img").css('background-image', 'url('+$img+')');

I've tried 开发者_StackOverflowputting fade in so many places.

Thanks

---

This is probably what you wanted:

$('#elem').fadeTo('slow', 0.3, function()
{
    $(this).css('background-image', 'url(' + $img + ')');
}).fadeTo('slow', 1);

With a 1 second delay:

$('#elem').fadeTo('slow', 0.3, function()
{
    $(this).css('background-image', 'url(' + $img + ')');
}).delay(1000).fadeTo('slow', 1);

---

Can I offer an alternative solution?

I had this same issue, and fade didn't work because it faded the entire element, not just the background. In my case the element was body, so I only wanted to fade the background.

An elegant way to tackle this is to class the element and use CSS3 transition for the background.

transition: background 0.5s linear;

When you change the background, either with toggleClass or with your code, $("#large-img").css('background-image', 'url('+$img+')'); it will fade as defined by the class.

---

This was the only reasonable thing I found to fade a background image.

<div id="foo">
  <!-- some content here -->
</div>

Your CSS; now enhanced with CSS3 transition.

#foo {
  background-image: url(a.jpg);
  transition: background 1s linear;
}

Now swap out the background

document.getElementById("foo").style.backgroundImage = "url(b.jpg)";

Voilà, it fades!

---

Obvious disclaimer: if your browser doesn't support the CSS3 transition property, this won't work. In which case, the image will change without a transition. Given <1% of your users' browser don't support CSS3, that's probably fine. Don't kid yourself, it's fine.

---

Building on Rampant Creative Group's solution above, I was using jQuery to change the background image of the body tag:

e.g.

$('body').css({'background': 'url(/wp-content/themes/opdemand/img/bg-sea.jpg) fixed', 'background-size': '100% 100%'});

$('body').css({'background': 'url(/wp-content/themes/opdemand/img/bg-trees.jpg) fixed', 'background-size': '100% 100%'});

I had a javascript timer that switched between the two statements.

All I had to do to solve the issue of creating a fadeOut -> fadeIn effect was use Rampant Creative Group's suggestion and add

transition: background 1.5s linear;

to my code. Now it fades out and in beautifully.

Thanks Rampant Creative Group's and SoupEnvy for the edit!!

---

Someone pointed me to this thread because I had this same issue but it didn't work for me. After hours of searching I found a solution using this - https://github.com/rewish/jquery-bgswitcher#readme

It has a few other options other than fade too.

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Opacity serves your purpose?

If so, try this:

$('#elem').css('opacity','0.3')

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If your trying to fade the backgound image but leave the foreground text/images you could use css to separate the background image into a new div and position it over the div containing the text/images then fade the background div.

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This may help

HTML

<div id="textcontainer">        
    <span id="sometext">This is some information </span>
    <div id="container">

    </div>
</div>

CSS

#textcontainer{
    position:relative;
    border:1px solid #000;
    width :300px;
    height:300px;
}
#container{
    background-image :url("http://dcooper.org/gallery/cf_appicon.jpg");
    width :100%;
    height:100%;
}
#sometext{
    position:absolute;
    top:50%;
    left:50%;
}

Js

$('#container').css('opacity','.1');