Dojo: The Definitive Guide

DOM Utilities

Recall that Dojo intentionally does not attempt to replace core JavaScript functionality; on the contrary, it only augments it where value can be added so that you can write portable code and incur less boilerplate. For this reason, you won't see direct replacements for common DOM operations such as appendChild, removeChild, and so on. Still, there are many utilities that could make DOM manipulation a lot simpler, and this section is all about how Base helps to make that happen.

Ancestry

Base packs several useful functions that augment and supplement common DOM functions. The first of these functions, isDescendant, shown in Table 2-1, is self-descriptive. You provide it two arguments (id values or actual nodes), where the first argument is the node of interest and the second argument is a potential ancestor. If the node of interest is in fact a member of the potential ancestor's DOM tree, the function returns true.

Table 2-1. Base function for manipulating and handling the DOM

Name	Return type	Comment
dojo.isDescendant(/*String | DomNode*/node, /* String | DomNode*/potentialAncestor)	Boolean	Returns a Boolean value indicating if a node has a particular ancestor or not and works in nested hierarchies as would be expected.

Selectability

The need to make a text on the page unselectable via the cursor is not uncommon and sometimes can actually enhance usability. Virtually every browser has a specific way of accomplishing this task, but no need to worry—you have Dojo. Whenever the ...