Proficient in CSS and HTML design patterns chapter 2 (image)

I. Images

ALT in the image: when the image is not downloaded successfully, the properties corresponding to ALT are displayed. When you move the mouse up, The ALT content is displayed.

JPG (full name JPEG ):Supports 16 million colors and lossy compression. To the extent of compression, You can compress data at will from scratch. The larger the compression volume, the smaller the file size and the lower the quality, JPG does not support transparent background

GIF:The most suitable format for artistic lines and computer synthetic images is to support up to 256 colors. To get more colors, the image software uses Jitter to simulate those colors. Supports transparent background color.

PNG:The PNG format is an improvement for GIF. It supports 16 million colors and cannot be monitored or lossless. Both IE7 and mainstream browsers support lossless compression, whereas IE6 does not.

 

Ii. Image Map 

An image map uses an image associated with a map element. The map element defines multiple clickable areas.

A map contains one or more area elements. Each area element defines the clickable range of an image. Each region cannot overlap. If this happens, the order of the area Elements in the document determines the stacking order.

An area element has four required attributes: href, ALT, shape, and coords.

The href attribute is the URL of another link that the browser jumps to when the user clicks this area.

The ALT attribute is used by the reader to describe the corresponding link-it is invisible.

The shape attribute describes the shape of a region. It can be a rect (rectangle), a circle, or a polygon ).

Coord: rect (rectangle) -- X, Y, X1, Y1 represents the lower right corner of the rectangle in the upper left corner (x1, Y1) of the (x, y) rectangle.

Circle -- X, Y, R represents (x, y) center r -- represents the radius

Poly (polygon) -- X1, Y1, X2, Y2, X3, Y3, X4, and Y4 represent vertices of a polygon.

 

3. Fade Out

1. blend the gradient color into the background color, and transition to the background color.

IV,