Freelance web design - CHAPTER 3 CONTENT CHUNKING PATTERN nor accessible
Tuesday, July 31st, 2007CHAPTER 3 CONTENT CHUNKING PATTERN nor accessible because the method getElementById returns only a single HTML element instance. Unlike the getElementsByTagName method, the returned element is not guaranteed to be a certain type other than having the parameter identifier equal to the id attribute. As a result, the object model referenced after the getElementById method may or may not apply to the found element. In the case of the property innerHTML, that is not a problem because virtually all visible elements have the innerHTML property. What could be more problematic is if the identifier assumed the retrieved element were a table when in fact the element is a table cell. At that point, the object model referencing would result in an exception. When writing JavaScript code that dynamically retrieves an HTML element(s), it is a good idea to test the found element before manipulating it. As a rule of thumb, when using getElementsByTag, you know what the HTML elements are but do not know where they are or what they represent. When using getElementById, you know what the found HTML element represents and where it is, but do not know the type and hence the object hierarchy. Understanding the Special Nature of innerHTML The property innerHTML is special in that it seems simple to use but can have devastating consequences. To illustrate the problem, consider the following HTML code:
| Nothing | Second cell |
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