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## org.w3c.dom
Interface Element

All Known Subinterfaces:
  CauchoElement

public interface Element
extends Node

By far the vast majority of objects (apart from text) that authors encounter when traversing a document are `Element` nodes. Assume the following XML document:<elementExample id="demo"> <subelement1/> <subelement2><subsubelement/></subelement2> </elementExample>

When represented using DOM, the top node is an `Element` node for "elementExample", which contains two child `Element` nodes, one for "subelement1" and one for "subelement2". "subelement1" contains no child nodes.

Elements may have attributes associated with them; since the `Element` interface inherits from `Node`, the generic `Node` interface method `getAttributes` may be used to retrieve the set of all attributes for an element. There are methods on the `Element` interface to retrieve either an `Attr` object by name or an attribute value by name. In XML, where an attribute value may contain entity references, an `Attr` object should be retrieved to examine the possibly fairly complex sub-tree representing the attribute value. On the other hand, in HTML, where all attributes have simple string values, methods to directly access an attribute value can safely be used as a convenience.

Fields inherited from interface org.w3c.dom.Node
`ATTRIBUTE_NODE, CDATA_SECTION_NODE, COMMENT_NODE, DOCUMENT_FRAGMENT_NODE, DOCUMENT_NODE, DOCUMENT_TYPE_NODE, ELEMENT_NODE, ENTITY_NODE, ENTITY_REFERENCE_NODE, NOTATION_NODE, PROCESSING_INSTRUCTION_NODE, TEXT_NODE`

Method Summary
`java.lang.String` | `getAttribute(java.lang.String name)` Retrieves an attribute value by name.
`Attr` | `getAttributeNode(java.lang.String name)` Retrieves an `Attr` node by name.
`NodeList` | `getElementsByTagName(java.lang.String name)` Returns a `NodeList` of all descendant elements with a given tag name, in the order in which they would be encountered in a preorder traversal of the `Element` tree.
`java.lang.String` | `getTagName()` The name of the element.
`void` | `normalize()` Puts all `Text` nodes in the full depth of the sub-tree underneath this `Element` into a "normal" form where only markup (e.g., tags, comments, processing instructions, CDATA sections, and entity references) separates `Text` nodes, i.e., there are no adjacent `Text` nodes.
`void` | `removeAttribute(java.lang.String name)` Removes an attribute by name.
`Attr` | `removeAttributeNode(Attr oldAttr)` Removes the specified attribute.
`void` | `setAttribute(java.lang.String name, java.lang.String value)` Adds a new attribute.
`Attr` | `setAttributeNode(Attr newAttr)` Adds a new attribute.

Methods inherited from interface org.w3c.dom.Node
`appendChild, cloneNode, getAttributes, getChildNodes, getFirstChild, getLastChild, getNextSibling, getNodeName, getNodeType, getNodeValue, getOwnerDocument, getParentNode, getPreviousSibling, hasChildNodes, insertBefore, removeChild, replaceChild, setNodeValue`

Method Detail

### getTagName

    public java.lang.String getTagName()

  The name of the element. For example, in: <elementExample id="demo"> ... </elementExample> , `tagName` has the value `"elementExample"`. Note that this is case-preserving in XML, as are all of the operations of the DOM. The HTML DOM returns the `tagName` of an HTML element in the canonical uppercase form, regardless of the case in the source HTML document.

### getAttribute

    public java.lang.String getAttribute(java.lang.String name)

  Retrieves an attribute value by name.
  Parameters:
    `name` - The name of the attribute to retrieve.
  Returns:
    The `Attr` value as a string, or the empty string if that attribute does not have a specified or default value.

### setAttribute

    public void setAttribute(java.lang.String name,
                             java.lang.String value)
                      throws DOMException

  Adds a new attribute. If an attribute with that name is already present in the element, its value is changed to be that of the value parameter. This value is a simple string, it is not parsed as it is being set. So any markup (such as syntax to be recognized as an entity reference) is treated as literal text, and needs to be appropriately escaped by the implementation when it is written out. In order to assign an attribute value that contains entity references, the user must create an `Attr` node plus any `Text` and `EntityReference` nodes, build the appropriate subtree, and use `setAttributeNode` to assign it as the value of an attribute.
  Parameters:
    `name` - The name of the attribute to create or alter.
    `value` - Value to set in string form.
  Throws:
    DOMException - INVALID_CHARACTER_ERR: Raised if the specified name contains an invalid character.
    NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

### removeAttribute

    public void removeAttribute(java.lang.String name)
                         throws DOMException

  Removes an attribute by name. If the removed attribute has a default value it is immediately replaced.
  Parameters:
    `name` - The name of the attribute to remove.
  Throws:
    DOMException - NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

### getAttributeNode

    public Attr getAttributeNode(java.lang.String name)

  Retrieves an `Attr` node by name.
  Parameters:
    `name` - The name of the attribute to retrieve.
  Returns:
    The `Attr` node with the specified attribute name or `null` if there is no such attribute.

### setAttributeNode

    public Attr setAttributeNode(Attr newAttr)
                          throws DOMException

  Adds a new attribute. If an attribute with that name is already present in the element, it is replaced by the new one.
  Parameters:
    `newAttr` - The `Attr` node to add to the attribute list.
  Returns:
    If the `newAttr` attribute replaces an existing attribute with the same name, the previously existing `Attr` node is returned, otherwise `null` is returned.
  Throws:
    DOMException - WRONG_DOCUMENT_ERR: Raised if `newAttr` was created from a different document than the one that created the element.
    NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
    INUSE_ATTRIBUTE_ERR: Raised if `newAttr` is already an attribute of another `Element` object. The DOM user must explicitly clone `Attr` nodes to re-use them in other elements.

### removeAttributeNode

    public Attr removeAttributeNode(Attr oldAttr)
                             throws DOMException

  Removes the specified attribute.
  Parameters:
    `oldAttr` - The `Attr` node to remove from the attribute list. If the removed `Attr` has a default value it is immediately replaced.
  Returns:
    The `Attr` node that was removed.
  Throws:
    DOMException - NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
    NOT_FOUND_ERR: Raised if `oldAttr` is not an attribute of the element.

### getElementsByTagName

    public NodeList getElementsByTagName(java.lang.String name)

  Returns a `NodeList` of all descendant elements with a given tag name, in the order in which they would be encountered in a preorder traversal of the `Element` tree.
  Parameters:
    `name` - The name of the tag to match on. The special value "*" matches all tags.
  Returns:
    A list of matching `Element` nodes.

### normalize

    public void normalize()

  Puts all `Text` nodes in the full depth of the sub-tree underneath this `Element` into a "normal" form where only markup (e.g., tags, comments, processing instructions, CDATA sections, and entity references) separates `Text` nodes, i.e., there are no adjacent `Text` nodes. This can be used to ensure that the DOM view of a document is the same as if it were saved and re-loaded, and is useful when operations (such as XPointer lookups) that depend on a particular document tree structure are to be used.

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