可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试):

问题:

I have an issue with background-position in mobile safari. It works fine on other desktop browsers, but not on iPhone or iPad.

body {
 background-color: #000000;
 background-image: url('images/background_top.png');
 background-repeat: no-repeat;
 background-position: center top;
 overflow: auto;
 padding: 0px;
 margin: 0px;
 font-family: "Arial";
}

#header {
 width: 1030px;
 height: 215px;
 margin-left: auto;
 margin-right: auto;
 margin-top: 85px;
 background-image: url('images/header.png');
}

#main-content {
 width: 1000px;
 height: auto;
 margin-left: auto;
 margin-right: auto;
 padding-left: 15px;
 padding-right: 15px;
 padding-top: 15px;
 padding-bottom: 15px;
 background-image: url('images/content_bg.png');
 background-repeat: repeat-y;
}

#footer {
 width: 100%;
 height: 343px;
 background-image: url('images/background_bottom.png');
 background-position: center;
 background-repeat: no-repeat;
}

Both "background_top.png" and "background_bottom.png" are shifted too far to the left. I've googled around, and as far as I can tell, background-position IS supported in mobile safari. I've also tried every combination of keywords ("top", "center", etc.), px, and %. Any thoughts?

Thanks!

Update: here's the markup in the .html file, which displays the design & layout fine in other browsers: (I also updated the above css)

<html lang="en">
 <head>
  <title>Title</title>
  <link rel="Stylesheet" type="text/css" href="styles.css" />
 </head>
 <body>
  <div id="header"></div>
  <div id="main-content"></div>
  <div id="footer"></div>
 </body>
</html>

Both background images are very wide (~2000px) so as to take up space on any sized browser.

P.S. I know that there's probably a few more efficient CSS shortcuts I could be using, but for now I like having the code organized like I have it for visibility.

回答1:

The iPhone/Webkit browser cannot center align background images when placed in the body tag. The only way around this is to remove the background image from your body tag and use an additional DIV as a wrapper.

#wrapper {
 background-color: #000000;
 background-image: url('images/background_top.png');
 background-repeat: no-repeat;
 background-position: center top;
 overflow: auto;
}


<html lang="en">
 <head>
  <title>Title</title>
  <link rel="Stylesheet" type="text/css" href="styles.css" />
 </head>
 <body>
  <div id="wrapper">
    <div id="header"></div>
    <div id="main-content"></div>
    <div id="footer"></div>
  </div>
 </body>
</html>

回答2:

Apparently, when you "scroll" on an iPhone / iPad, you're not scrolling the page in the same way as you do in a desktop browser. What you're doing is more like moving the whole page within a viewport. (I'm sure someone will correct me if I'm using the wrong terminology here.)

This means that background-position: fixed is still "supported" but has no real effect, since the whole page is moving within the viewport rather than the page content scrolling within the page.

回答3:

It'll work with

background-position-x: 50%;
background-position-y: 0%;

and still add

background-position: center top;

for other browsers.

回答4:

Create a wrapper ID to place in the body, then include the following CSS:

#background_wrap {
    z-index: -1;
    position: fixed;
    top: 0;
    left: 0;
    height: 100%;
    width: 100%;
    background-size: cover;
    background-image: url('../images/compressed/background-mobile.png');
    background-repeat: no-repeat;
    background-attachment: scroll;
}

Just ensure that none of your content goes within the div otherwise the whole page will be fixed with no scrolling.

回答5:

I have this problem and I'm addressing it by getting rid of my fixed footer using a separate style as mentioned here: How to target CSS for iPad but exclude Safari 4 desktop using a media query?