Up: Parsing HTML/XML

31.26.1 Document Object Model

The DOM returned by libxml-parse-html-region (and the other XML parsing functions) is a tree structure where each node has a node name (called a tag), and optional key/value attribute list, and then a list of child nodes. The child nodes are either strings or DOM objects.

     (body ((width . "101"))
      (div ((class . "thing"))
       "Foo"
       (div nil
        "Yes")))
— Function: dom-node tag &optional attributes &rest children

This function creates a DOM node of type tag. If given, attributes should be a key/value pair list. If given, children should be DOM nodes.

The following functions can be used to work with this structure. Each function takes a DOM node, or a list of nodes. In the latter case, only the first node in the list is used.

Simple accessors:

dom-tag node
Return the tag (also called “node name”) of the node.
dom-attr node attribute
Return the value of attribute in the node. A common usage would be:
          (dom-attr img 'href)
          => "http://fsf.org/logo.png"

dom-children node
Return all the children of the node.
dom-non-text-children node
Return all the non-string children of the node.
dom-attributes node
Return the key/value pair list of attributes of the node.
dom-text node
Return all the textual elements of the node as a concatenated string.
dom-texts node
Return all the textual elements of the node, as well as the textual elements of all the children of the node, recursively, as a concatenated string. This function also takes an optional separator to be inserted between the textual elements.
dom-parent dom node
Return the parent of node in dom.

The following are functions for altering the DOM.

dom-set-attribute node attribute value
Set the attribute of the node to value.
dom-append-child node child
Append child as the last child of node.
dom-add-child-before node child before
Add child to node's child list before the before node. If before is nil, make child the first child.
dom-set-attributes node attributes
Replace all the attributes of the node with a new key/value list.

The following are functions for searching for elements in the DOM. They all return lists of matching nodes.

dom-by-tag dom tag
Return all nodes in dom that are of type tag. A typical use would be:
          (dom-by-tag dom 'td)
          => '((td ...) (td ...) (td ...))

dom-by-class dom match
Return all nodes in dom that have class names that match match, which is a regular expression.
dom-by-style dom style
Return all nodes in dom that have styles that match match, which is a regular expression.
dom-by-id dom style
Return all nodes in dom that have IDs that match match, which is a regular expression.
dom-strings dom
Return all strings in dom.

Utility functions:

dom-pp dom &optional remove-empty
Pretty-print dom at point. If remove-empty, don't print textual nodes that just contain white-space.