XMLDOM属性列表

The Microsoft XML Parser

To create an XML Document object with JavaScript, use the following code:

var xmlDoc=new ActiveXObject("Microsoft.XMLDOM")
xmlDoc.appendChild(xmlDoc.createElement("root"))

XML Parser in Mozilla Browsers

Plain XML documents are displayed in a tree-like structure in Mozilla (just like IE).

Mozilla also supports parsing of XML data that resides in a file, using JavaScript. The parsed data can be displayed as HTML.

To create an XML Document object with JavaScript in Mozilla, use the following code:

var xmlDoc=document.implementation.createDocument("ns","root",null)

The first parameter, ns, defines the namespace used for the XML document. The second parameter, root, is the XML root element in the XML file. The third parameter, null, is always null because it is not implemented yet.

Loading an XML File Into the Parser

The following code loads an existing XML document ("note.xml") into the XML parser:

<script type="text/javascript">

var xmlDoc=new ActiveXObject("Microsoft.XMLDOM")
xmlDoc.async="false"
xmlDoc.load("note.xml")
...
...
...
</script>//ie和firefox都支持load,firefox不支持loadXML(string text)

The first line of the script creates an instance of the Microsoft XML parser. The third line tells the parser to load an XML document called "note.xml". The second line turns off asynchronized loading, to make sure that the parser will not continue execution of the script before the document is fully loaded.

Accessing XML Elements by Name

Addressing elements by number is NOT the preferred way to extract elements from XML documents. Using names is a better way:

<script type="text/javascript">
function loadXML()
{
var xmlDoc=new ActiveXObject("Microsoft.XMLDOM")
xmlDoc.async="false"
xmlDoc.load("note.xml")//注意firefox的load("note.xml")并不会读该文件,须要给fox增加loadXML()涵数

xmlDoc.getElementsByTagName("to").item(0).text
xmlDoc.getElementsByTagName("from").item(0).text
xmlDoc.getElementsByTagName("heading").item(0).text
xmlDoc.getElementsByTagName("body").item(0).text
}
</script>

Important: To extract the text (Jani) from an element like this: <from>Jani</from>, the syntax is: getElementsByTagName("from").item(0).text, and NOT like this: getElementsByTagName("from").text. The reason for this is that the result returned from getElementsByTagName is an array of nodes, containing all nodes found within the XML document with the specified tag name (in this case "from").

The XMLHttpRequest object is supported in Internet Explorer 5.0+, Safari 1.2, Mozilla 1.0 / Firefox, and Netscape 7.


What is an HTTP Request?

With an HTTP request, a web page can make a request to, and get a response from a web server - without reloading the page. The user will stay on the same page, and he or she will not notice that scripts might request pages, or send data to a server in the background.

By using the XMLHttpRequest object, a web developer can change a page with data from the server after the page has loaded.

Google Suggest is using the XMLHttpRequest object to create a very dynamic web interface: When you start typing in Google's search box, a JavaScript sends the letters off to a server and the server returns a list of suggestions.

Creating an XMLHttpRequest Object

For Mozilla, Firefox, Safari, and Netscape:

var xmlhttp=new XMLHttpRequest()

For Internet Explorer:

var xmlhttp=new ActiveXObject("Microsoft.XMLHTTP")

Example

<script type="text/javascript">
var xmlhttp
function loadXMLDoc(url)
{
// code for Mozilla, etc.
if (window.XMLHttpRequest)
{
xmlhttp=new XMLHttpRequest()
xmlhttp.onreadystatechange=xmlhttpChange
xmlhttp.open("GET",url,true)
xmlhttp.send(null)
}
// code for IE
else if (window.ActiveXObject)
{
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP")
if (xmlhttp)
{
xmlhttp.onreadystatechange=xmlhttpChange
xmlhttp.open("GET",url,true)
xmlhttp.send()
}
}
}
function xmlhttpChange()
{
// if xmlhttp shows "loaded"
if (xmlhttp.readyState==4)
{
// if "OK"
if (xmlhttp.status==200)
{
// ...some code here...
}
else
{
alert("Problem retrieving XML data")
}
}
}
</script>

Why are we Using async in our Examples?

Most of the examples here use the async mode (the third parameter of open() set to true).

The async parameter specifies whether the request should be handled asynchronously or not. True means that script continues to run after the send() method, without waiting for a response from the server. false means that the script waits for a response before continuing script processing. By setting this parameter to false, you run the risk of having your script hang if there is a network or server problem, or if the request is long (the UI locks while the request is being made) a user may even see the "Not Responding" message. It is safer to send asynchronously and design your code around the onreadystatechange event

The XMLHttpRequest Object Reference

Methods

MethodDescription
abort()Cancels the current request
getAllResponseHeaders()Returns the complete set of http headers as a string
getResponseHeader("headername")Returns the value of the specified http header
open("method","URL",async,"uname","pswd")Specifies the method, URL, and other optional attributes of a request

The method parameter can have a value of "GET", "POST", or "PUT" (use "GET" when requesting data and use "POST" when sending data (especially if the length of the data is greater than 512 bytes.

The URL parameter may be either a relative or complete URL.

The async parameter specifies whether the request should be handled asynchronously or not. true means that script processing carries on after the send() method, without waiting for a response. false means that the script waits for a response before continuing script processing

send(content)Sends the request
setRequestHeader("label","value")Adds a label/value pair to the http header to be sent

Properties

PropertyDescription
onreadystatechangeAn event handler for an event that fires at every state change
readyStateReturns the state of the object:

0 = uninitialized
1 = loading
2 = loaded
3 = interactive
4 = complete

responseTextReturns the response as a string
responseXMLReturns the response as XML. This property returns an XML document object, which can be examined and parsed using W3C DOM node tree methods and properties
statusReturns the status as a number (e.g. 404 for "Not Found" or 200 for "OK")
statusTextReturns the status as a string (e.g. "Not Found" or "OK")

XML DOM Node Types

The DOM Structure

The DOM presents a document as a hierarchy of node objects.

The following table lists the different W3C node types, and which node types they may have as children:

Node typeDescriptionChildren
DocumentRepresents the entire document (it is the root-node of the DOM tree)Element (max. one), ProcessingInstruction, Comment, DocumentType
DocumentFragmentRepresents a "lightweight" Document object, which can hold a portion of a documentElement, ProcessingInstruction, Comment, Text, CDATASection, EntityReference
DocumentTypeRepresents a list of the entities that are defined for the documentNone
EntityReferenceRepresents an entity referenceElement, ProcessingInstruction, Comment, Text, CDATASection, EntityReference
ElementRepresents an elementElement, Text, Comment, ProcessingInstruction, CDATASection, EntityReference
AttrRepresents an attributeText, EntityReference
ProcessingInstructionRepresents a "processing instruction"None
CommentRepresents a commentNone
TextRepresents textual content (character data) in an element or attributeNone
CDATASectionRepresents a block of text that may contains characters that would otherwise be treated as markupNone
EntityRepresents an entityElement, ProcessingInstruction, Comment, Text, CDATASection, EntityReference
NotationRepresents a notation declared in the DTDNone


Node Types - Return Values

Below is a list of what the nodeName and the nodeValue properties will return for each nodetype:

Node typenodeName returnsnodeValue returns
Document#documentnull
DocumentFragment#document fragmentnull
DocumentTypedoctype namenull
EntityReferenceentity reference namenull
Elementelement namenull
Attrattribute nameattribute value
ProcessingInstructiontargetcontent of node
Comment#commentcomment text
Text#textcontent of node
CDATASection#cdata-sectioncontent of node
Entityentity namenull
Notationnotation namenull


NodeTypes - Named Constants

NodeTypeNamed Constant
1ELEMENT_NODE
2ATTRIBUTE_NODE
3TEXT_NODE
4CDATA_SECTION_NODE
5ENTITY_REFERENCE_NODE
6ENTITY_NODE
7PROCESSING_INSTRUCTION_NODE
8COMMENT_NODE
9DOCUMENT_NODE
10DOCUMENT_TYPE_NODE
11DOCUMENT_FRAGMENT_NODE
12NOTATION_NODE

XML DOM - The Attr Object

The Attr object

The attr object represents an attribute of an element object.

The attr object's properties and methods are described below:

Properties

PropertyDescription
attributesReturns a NamedNodeMap that contains all attributes of a node
childNodesReturns a node list that contains all children of a node
firstChildReturns the first child node of a node
lastChildReturns the last child node of a node
nameReturns the name of the attribute
nextSiblingReturns the node immediately following a node. Two nodes are siblings if they have the same parent node
nodeNameReturns the name of the node (depending on the node type)
nodeTypeReturns the node type as a number
nodeValueReturns the value of the node
ownerDocumentReturns the Document object of a node (returns the root node of the document)
parentNodeReturns the parent node of a node
previousSiblingReturns the node immediately preceding a node. Two nodes are siblings if they have the same parent node
valueReturns the value of the attribute

Methods

MethodDescription
appendChild(tagname)Appends a new child node to a node
cloneNode(boolean)Creates an exact clone node of a node. If the boolean parameter is set to true, the cloned node clones all the child nodes of the original node as well
hasChildNodes()Returns true if a node has child nodes. Otherwise it returns false
insertBefore(newnode,refnode)Inserts a new node (newnode) before the existing node (refnode)
removeChild(nodename)Removes the specified node and returns it
replaceChild(newnode,oldnode)Replaces the oldnode with the newnode, and returns the oldnode

The CDATASection  comment object

The CDATASection object represents CDATASection nodes in a document. A CDATASection node is used to escape parts of text which normally would be recognized as markup.

The CDATASection object's properties and methods are described below:

Properties

PropertyDescription
attributesReturns a NamedNodeMap that contains all attributes of a node
childNodesReturns a node list that contains all children of a node
dataReturns the data of the node
firstChildReturns the first child node of a node
lastChildReturns the last child node of a node
lengthReturns the length of the data (in characters)
nextSiblingReturns the node immediately following a node. Two nodes are siblings if they have the same parent node
nodeNameReturns the name of the node (depending on the node type)
nodeTypeReturns the node type as a number
nodeValueReturns the value of the node
ownerDocumentReturns the Document object of a node (returns the root node of the document)
parentNodeReturns the parent node of a node
previousSiblingReturns the node immediately preceding a node. Two nodes are siblings if they have the same parent node

Methods

MethodDescription
appendChild(tagname)Appends a new child node to a node
appendData(strdata)Appends the specified string to the existing data
cloneNode(boolean)Creates an exact clone node of a node. If the boolean parameter is set to true, the cloned node clones all the child nodes of the original node as well
deleteData(offset,count)Removes the specified range of characters from the data
hasChildNodes()Returns true if a node has child nodes. Otherwise it returns false
insertBefore(newnode,refnode)Inserts a new node (newnode) before the existing node (refnode)
insertData(offset,string)Inserts the stringdata at the specified offset
removeChild(nodename)Removes the specified node and returns it
replaceChild(newnode,oldnode)Replaces the oldnode with the newnode, and returns the oldnode
replaceData(offset,count,stringdata)Replaces the characters from the specified offset with the stringdata

The Document object

The document object is the root element in the node-tree. All nodes in the node tree are child nodes of the document object.

The document object's properties, methods, and events are described below:

Properties

PropertyDescription
attributesReturns a NamedNodeMap that contains all attributes of a node
childNodesReturns a node list that contains all children of a node
doctypeReturns the DTD or Schema for the document
documentElementReturns the root element of the document
firstChildReturns the first child node of a node
implementationReturns the DOMImplementation object for this particular document
lastChildReturns the last child node of a node
nextSiblingReturns the node immediately following a node. Two nodes are siblings if they have the same parent node
nodeNameReturns the name of the node
nodeTypeReturns the node type as a number
nodeValueReturns the value of the node
ownerDocumentReturns the Document object of a node (returns the root node of the document)
parentNodeReturns the parent node of a node
previousSiblingReturns the node immediately preceding a node. Two nodes are siblings if they have the same parent node

Methods

MethodDescription
appendChild(tagname)Appends a new child node to a node
cloneNode(boolean)Creates an exact clone node of a node. If the boolean parameter is set to true, the cloned node clones all the child nodes of the original node as well
createAttribute(attrname)Creates an Attr node with the specified name
createCDATASection(text)Creates a CDATASection node, containing the specified text
createComment(text)Creates a comment node, containing the specified text
createDocumentFragment()Creates an empty documentFragment object
createElement(tagname)Creates an element node with the specified name
createEntityReference(refname)Creates an entityReference node with the specified name
createProcessingInstruction(target,text)Creates a processingInstruction node, containing the specified target and text
createTextNode(text)Creates a text node, containing the specified text
getElementsByTagName(tagname)Returns the specified node, and all its child nodes, as a node list
hasChildNodes()Returns true if a node has child nodes. Otherwise it returns false
insertBefore(newnode,refnode)Inserts a new node (newnode) before the existing node (refnode)
removeChild(nodename)Removes the specified node and returns it
replaceChild(newnode,oldnode)Replaces the oldnode with the newnode, and returns the oldnode

The Element object

The element object represents the element nodes in the document. If the element node contains text, this text is represented in a text node.

The element object's properties and methods are described below:

Properties

PropertyDescription
attributesReturns a NamedNodeMap that contains all attributes of a node
childNodesReturns a node list that contains all children of a node
firstChildReturns the first child node of a node
lastChildReturns the last child node of a node
nextSiblingReturns the node immediately following a node. Two nodes are siblings if they have the same parent node
nodeNameReturns the name of the node (depending on the node type)
nodeTypeReturns the node type as a number
nodeValueReturns the value of the node
ownerDocumentReturns the Document object of a node (returns the root node of the document)
parentNodeReturns the parent node of a node
previousSiblingReturns the node immediately preceding a node. Two nodes are siblings if they have the same parent node
tagNameReturns the name of the element node

Methods

MethodDescription
appendChild(tagname)Appends a new child node to a node
cloneNode(boolean)Creates an exact clone node of a node. If the boolean parameter is set to true, the cloned node clones all the child nodes of the original node as well
getAttribute(attrname)Returns the value of the specified attribute
getAttributeNode(attrname)Returns the specified attribute node as an Attr object
getElementsByTagName(tagname)Returns the specified node, and all its child nodes, as a node list
hasChildNodes()Returns true if a node has child nodes. Otherwise it returns false
insertBefore(newnode,refnode)Inserts a new node (newnode) before the existing node (refnode)
normalize()Combines all subtree Text nodes into a single one
removeAttribute(attrname)Removes the specified attribute's value
removeAttributeNode(attriname)Removes the specified attribute node
removeChild(nodename)Removes the specified node and returns it
replaceChild(newnode,oldnode)Replaces the oldnode with the newnode, and returns the oldnode
setAttribute(attrname,attrvalue)Sets the value of the named attribute
setAttributeNode(attrname)Inserts the specified new attribute to the element

The Node Object

The node object represents a node in the node-tree.

The node object's properties and methods are described below:

Properties

PropertyDescription
attributesReturns a NamedNodeMap that contains all attributes of a node
childNodesReturns a node list that contains all children of a node
firstChildReturns the first child node of a node
lastChildReturns the last child node of a node
nextSiblingReturns the node immediately following a node. Two nodes are siblings if they have the same parent node
nodeNameReturns the name of the node (depending on the node type)
nodeTypeReturns the node type as a number
nodeValueReturns the value of the node
ownerDocumentReturns the Document object of a node (returns the root node of the document)
parentNodeReturns the parent node of a node
previousSiblingReturns the node immediately preceding a node. Two nodes are siblings if they have the same parent node

Methods

MethodDescription
appendChild(tagname)Appends a new child node to a node
cloneNode(boolean)Creates an exact clone node of a node. If the boolean parameter is set to true, the cloned node clones all the child nodes of the original node as well
hasChildNodes()Returns true if a node has child nodes. Otherwise it returns false
insertBefore(newnode,refnode)Inserts a new node (newnode) before the existing node (refnode)
removeChild(nodename)Removes the specified node and returns it
replaceChild(newnode,oldnode)Replaces the oldnode with the newnode, and returns the oldnode

The NodeList object

The nodeList object represents a node and its child nodes as a node-tree.

The nodeList object's properties and methods are described below:

Properties

PropertyDescription
lengthReturns the number of items in the node list

Methods

MethodDescription
item(index)Returns the item at the specified index in the node list

The Text object

The text object represents the text of an attribute or element object.

The text object's properties and methods are described below:

Properties

PropertyDescription
attributesReturns a NamedNodeMap that contains all attributes of a node
childNodesReturns a node list that contains all children of a node
dataReturns the data of the node
firstChildReturns the first child node of a node
lastChildReturns the last child node of a node
lengthReturns the length of the data (in characters)
nextSiblingReturns the node immediately following a node. Two nodes are siblings if they have the same parent node
nodeNameReturns the name of the node (depending on the node type)
nodeTypeReturns the node type as a number
nodeValueReturns the value of the node
ownerDocumentReturns the Document object of a node (returns the root node of the document)
parentNodeReturns the parent node of a node
previousSiblingReturns the node immediately preceding a node. Two nodes are siblings if they have the same parent node

Methods

MethodDescription
appendChild(tagname)Appends a new child node to a node
appendData(strdata)Appends the specified string to the existing data
cloneNode(boolean)Creates an exact clone node of a node. If the boolean parameter is set to true, the cloned node clones all the child nodes of the original node as well
deleteData(offset,count)Removes the specified range of characters from the data
hasChildNodes()Returns true if a node has child nodes. Otherwise it returns false
insertBefore(newnode,refnode)Inserts a new node (newnode) before the existing node (refnode)
insertData(offset,string)Inserts the stringdata at the specified offset
removeChild(nodename)Removes the specified node and returns it
replaceChild(newnode,oldnode)Replaces the oldnode with the newnode, and returns the oldnode
replaceData(offset,count,stringdata)Replaces the characters from the specified offset with the stringdata

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