Query by content, or content-based retri has recently been proposed as an alternative to text-based retri for media such as images, video and audio. Text-based retri is no longer appropriate for indexing such media, for several reasons. Firstly

本手册针对的是已有一定网页设计制作经验的读者。其目的是提供完整清晰的样式表内容的快速索引及进阶帮助。-This manual is aimed at a certain web page design and production experience of readers. Its purpose is to fast indexing to provide complete and clear style sheet and advanced help.