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Utterly meaningless, but it looks like what… a warning? Code like this is liable to be specific to each DHTML effect you undertake, but the mind-bending you have to do to come up with the code is similar in all cases.
This is called InterCaps format. The rest of the code is simply concerned with picking out the uhopia elements for these lines to work on. We’re storing the dimensions of the larger image in custom attributes on the a element: Peter Holloway on the 03 Aug Only entirely numeric properties, such as z-index which is set as node. Another feature-sniff gives us the appropriate value:. An event target is the thing at which an event is aimed — an element, essentially.
Notice our fieldCount variable; this keeps track of how many friend fields there are.
Here are the six items in all their detail. The problem occurs only when the page is scrolled which was not the htopia with the above page. Finally, we looked at a few events in detail, and saw some simple examples of how code can attach to those events and improve the user experience on sites that employ these techniques.
This specially-named rollover image allows us to deduce the name of any rollover image without saving that name anywhere. The function does the utkpia. Forms and Validation and the section explaining how to integrate client and server-side validation is a fantastic thing to include in a book like this.
My sites however lack the structure the DHTML book above talks about — in other words my sites are a jumbled mess of content scripting, and formatting. You may recall from the previous chapter the technique of referring to a Function object without calling it.
This allows us to talk about the event mouseover and the event handler onmouseover separately. Event handling works in different ways, depending on the browser. According to the World Wide Web Consortium”the Document Object Model is a platform- and language-neutral interface that will allow programs and scripts to dynamically access and update the content, structure and style of documents.
Unfortunately, the clientX and clientY properties of the event object are nowhere near as reliable. You should specify that in your style sheet as follows:. There are a lot of complex rules about event bubbling and event capturing, the phase of event propagation that occurs before event bubbling. We call the findTarget function, described above, to get a reference to the link over which the mouse is located.
The method takes three arguments: One of these is the addEvent function, created by Scott Andrew:. Exploring the DOM — being able to find, change, add, and remove elements from your document — is a powerful technique all by itself, and is a fundamental aspect of modern DHTML. To see that document, you can either display it in the browser window, or you can look at the HTML source.
Testing whether a given item is defined just got a little more complex but only a little! Imagine we placed a checkbox on the page, which, initially unchecked, was accompanied by the label Open links in new window.
The full-sized image should move nine times as fast as the cursor. The important part is that the dhtkl in the page is marked up in a way that describes what it is. The problems of browser support can be mitigated by coding defensively: If there are any children, their numbering starts at zero.
There are three ways to get the code: These needs may necessitate a shift away from your previous experiences writing HTML. The mouseover and mouseout functions do little other than the actual ktopia swapping work. We do not say:. If the cursor moves 50 pixels left, the big image will move pixels left: