How to Utilize Backgrounds for and/or
This guide addresses the different scenarios when applying backgrounds to HTML documents, clarifying why specific behaviors occur and providing solutions for achieving desired background effects.
Applying Backgrounds to and
It's essential to note that there's a difference when setting background properties on the and
elements in standards mode.- When applying a background to : The background will occupy the entire visible portion of the page, regardless of the actual size of the element.
- When applying a background to : The background will only cover the area occupied by the element, which is often larger than the visible area due to the default margins applied to the element. In such cases, the element's background color will "bleed" through the element.
Superimposing Backgrounds
To achieve effects like a background color with a semi-transparent image overlay, it's not necessary to use separate and
elements. Instead, utilize the background-color and background-image properties in conjunction:body {
background: #ddd url(background.png) center top no-repeat;
}
Combining Multiple Background Images
To combine multiple background images, you can utilize CSS2 techniques or take advantage of CSS3 enhancements:
- CSS2: Set different background images on both the and elements. Ensure the element has a defined height to accommodate the 's background:
html {
height: 100%;
background: #ddd url(background1.png) repeat;
}
body {
min-height: 100%;
background: transparent url(background2.png) center top no-repeat;
}
- CSS3: Utilize the multi-layered background syntax:
body {
background: url(background2.png) center top no-repeat, #ddd url(background1.png) repeat;
}
Providing Fallbacks
If your goal is to support older browsers, utilize the CSS2 method for applying multiple backgrounds as it's supported back to IE7. Keep in mind that the CSS3 multi-layered background syntax may result in only the bottommost layer having a background color.
The above is the detailed content of How to Effectively Use HTML `` and `` Backgrounds?. For more information, please follow other related articles on the PHP Chinese website!
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