Using before and after pseudo-elements on background image

问题

I am wanting to construct navigation items from three (background) images, with the first and last a fixed width, and the central a variable width, depending on the width of the text in the nav item. I have been led to believe that using the pseudo elements before and after would be the best method. When I try this though, the main (central) background image for the nav item is overlapping with the before and after background images.

You can see what I mean on this page.

Here is the CSS:

.box {
   background-image: url(nav/images/nav_02.png);
   background-repeat: repeat;
   height:20px;
   position: absolute;
   padding: 10px 13px;
}


.box:before {
    left: 0;
    background-image: url(nav/images/nav_01.png);
}

.box:after {
    right: 0;
    background-image: url(nav/images/nav_03.png);
}

.box:before,
.box:after {
    content: ' ';
    width: 13px;
    height:40px;
    position: absolute;
    top: 0;
    background-repeat: no-repeat
}

And the HTML:

<div class="box">here is some text</div>

Can I use background-images in this way using pseudo elements?

Thanks,

Nick

回答1:

Yes, but you will have to use left and right attributes for moving the pseudo elements in the right position. padding is not correct for the main box to position. Better use margin.

.box {
    background-repeat-x: repeat;
    background-image: url(nav/images/nav_02.png);
    background-repeat: repeat;
    height: 40px;
    position: absolute;
    margin: 0 13px;
    line-height: 40px;
}

.box:before, .box:after {
    content: ' ';
    display:block;
    width: 13px;
    height: 40px;
    position: absolute;
    top: 0;
    background-repeat: no-repeat;
}

.box:before {
    left: -13px;
    background-image: url(nav/images/nav_01.png);
}

.box:after {
    right: -13px;
    background-image: url(nav/images/nav_03.png);
}

来源：https://stackoverflow.com/questions/10871333/using-before-and-after-pseudo-elements-on-background-image

标签

html

background-image

pseudo-element