Requirements and application scenarios of absolute positioning strategy, specific code examples are required
Abstract: Absolute positioning (Absolute positioning) is a layout strategy commonly used in front-end development. This article will introduce the requirements and application scenarios of absolute positioning, and give specific code examples to help readers better understand and apply this strategy.
1. Requirements for absolute positioning
Absolute positioning refers to positioning the element relative to its nearest non-static positioned ancestor element by setting the element's position attribute to "absolute". The requirements for absolute positioning are as follows:
2. Application scenarios of absolute positioning
Absolute positioning has a wide range of application scenarios in front-end development, mainly including the following aspects:
<div id="box1"></div> <div id="box2"></div>
position: relative; width: 100%; height: 100%;
}
position: absolute; top: 0; left: 0; width: 50%; height: 100%; background-color: red;
}
position: absolute; top: 0; right: 0; width: 50%; height: 100%; background-color: blue;
}
In the above code example, we use absolute positioning to divide the container #container into two parallel parts, fill them with red and blue respectively, and implement a responsive layout.
<div id="box1"></div> <div id="box2"></div>
position: relative; width: 100%; height: 200px;
}
float: left; width: 50%; height: 100px; background-color: red;
}
position: absolute; top: 50px; right: 0; width: 50%; height: 100px; background-color: blue;
}
In the above code example, we set the two floating elements to left floating and use absolute positioning respectively, so that #box1 and #box2 achieve the arrangement effect on the left and right sides inside the parent element #container.
position: relative; width: 100%; height: 50px; background-color: gray;
}
#ul {
list-style: none; margin: 0; padding: 0;
}
.item {
display: inline-block; padding: 10px;
}
.dropdown {
position: absolute; top: 50px; left: 0; display: none;
}
.item:hover .dropdown {
display: block;
}
In the above code example, we use Absolute positioning positions the drop-down menu .dropdown relative to the navigation menu item .item, and implements the drop-down effect of the menu item through the pseudo-class selector:hover.
Conclusion:
Absolute positioning is a layout strategy commonly used in front-end development. The precise positioning of elements can be achieved by setting the position, top, bottom, left, right and z-index attributes of the element. The requirements for absolute positioning include determining the positioning reference object, setting the positioning coordinates, and adding the z-index attribute. Absolute positioning is widely used in scenarios such as responsive layout, floating element positioning, and navigation menu layout. Through the introduction of code examples, I believe readers can better understand and apply the absolute positioning strategy.
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