Bạn đã quen thuộc với ý tưởng rằng một loạt các container lồng nhau bao quanh một yếu tố được đưa ra trên trang web của bạn, Đơn giản chỉ cần tưởng tượng rằng bạn muốn có một phương pháp tham khảo đặc biệt với bất kỳ các yếu tố trong các container, | Chapter 12 Advanced Cascading Style Sheets You re already familiar with the idea that a series of nested containers surrounds a given element on your Web page right Simply imagine that you now want a method of referring uniquely to any of the elements in any of the containers and you see that this dot notation that is separating elements with a period makes sense. In fact by using a unique ID value all you really have in the preceding line is the following This line refers uniquely to the container paragraph that you designate as holmesl on the Web page. After you initially specify a unique element you can access a wide variety of different attributes of that container by further utilizing the dot notation. To get to visibility you must use the .style element and then specify the exact name of the attribute that you want. Conceptually it s as follows unique container After you specify the visibility attribute of the style of the holmesl paragraph you can change its value by using a simple assignment statement in JavaScript as follows visible I hope that makes a bit more sense. If you can t get the examples in this session to work perhaps your Web browser is tip using an older document model. If that s the case try using . visibility visible instead. JavaScript is all eventbased so to test this snippet of code I m going to associate the reassignment of visible to a simple event that occurs on all Web pages onload. After you specify this event in the body tag of a page onload enables you to easily specify JavaScript to execute as soon as the Web browser receives every element of the page from the network. Inline JavaScript looks a little bit different from inline CSS because you don t have a single attribute that you always use style. Instead you list the desired event with the associated JavaScript code on the right-hand side of the statement. The body tag of your .
