PHP Simple HTML DOM Parser 用法简介 – 苏demo的别样人生

源码下载地址是 http://simplehtmldom.sourceforge.net/

How to create HTML DOM object?

Quick way:

// Create a DOM object from a string
$html = str_get_html(‘<html><body>Hello!</body></html>’);

// Create a DOM object from a URL
$html = file_get_html(‘http://www.google.com/’);

// Create a DOM object from a HTML file
$html = file_get_html(‘test.htm’);

Object-oriented way:

// Create a DOM object
$html = new simple_html_dom();

// Load HTML from a string
$html->load(‘<html><body>Hello!</body></html>’);

// Load HTML from a URL
$html->load_file(‘http://www.google.com/’);

// Load HTML from a HTML file
$html->load_file(‘test.htm’);

How to find HTML elements?

Basics:

// Find all anchors, returns a array of element objects
$ret = $html->find(‘a‘);

// Find (N)th anchor, returns element object or null if not found (zero based)
$ret = $html->find(‘a‘, 0);

// Find all <div> which attribute id=foo
$ret = $html->find(‘div[id=foo]‘);

// Find all <div> with the id attribute
$ret = $html->find(‘div[id]‘);

// Find all element has attribute id
$ret = $html->find(‘[id]‘);

Advanced:

// Find all element which id=foo
$ret = $html->find(‘#foo‘);

// Find all element which class=foo
$ret = $html->find(‘.foo‘);

// Find all anchors and images
$ret = $html->find(‘a, img‘);

// Find all anchors and images with the “title” attribute
$ret = $html->find(‘a[title], img[title]‘);

Descendant selectors:

// Find all <li> in <ul>
$es = $html->find(‘ul li‘);

// Find Nested <div> tags
$es = $html->find(‘div div div‘);

// Find all <td> in <table> which class=hello
$es = $html->find(‘table.hello td‘);

// Find all td tags with attribite align=center in table tags
$es = $html->find(”table td[align=center]‘);

Nested selectors:

// Find all <li> in <ul>
foreach($html->find(‘ul‘) as $ul)
{
foreach($ul->find(‘li‘) as $li)
{
// do something…
}
}

// Find first <li> in first <ul>
$e = $html->find(‘ul‘, 0)->find(‘li‘, 0);

Attribute Filters:

Supports these operators in attribute selectors:

Filter	Description
[attribute]	Matches elements that have the specified attribute.
[attribute=value]	Matches elements that have the specified attribute with a certain value.
[attribute!=value]	Matches elements that don’t have the specified attribute with a certain value.
[attribute^=value]	Matches elements that have the specified attribute and itstarts with a certain value.
[attribute$=value]	Matches elements that have the specified attribute and itends with a certain value.
[attribute*=value]	Matches elements that have the specified attribute and itcontains a certain value.

Text & Comments:

// Find all text blocks
$es = $html->find(‘text‘);

// Find all comment (<!–…–>) blocks
$es = $html->find(‘comment‘);

How to access the HTML element’s attributes?

Get, Set and Remove attributes:

// Get a attribute ( If the attribute is non-value attribute (eg. checked, selected…), it will returns true or false)
$value = $e->href;

// Set a attribute(If the attribute is non-value attribute (eg. checked, selected…), set it’s value as true or false)
$e->href = ‘my link’;

// Remove a attribute, set it’s value as null!
$e->href = null;

// Determine whether a attribute exist?
if(isset($e->href))
echo ‘href exist!’;

Magic attributes:

// Example
$html = str_get_html(“<div>foo <b>bar</b></div>”);
$e = $html->find(“div”, 0);

echo $e->tag; // Returns: ” div”
echo $e->outertext; // Returns: ” <div>foo <b>bar</b></div>”
echo $e->innertext; // Returns: ” foo <b>bar</b>”
echo $e->plaintext; // Returns: ” foo bar”

Attribute Name	Usage
$e->tag	Read or write the tag name of element.
$e->outertext	Read or write the outer HTML text of element.
$e->innertext	Read or write the inner HTML text of element.
$e->plaintext	Read or write the plain text of element.

Tips:

// Extract contents from HTML
echo $html->plaintext;

// Wrap a element
$e->outertext = ‘<div class=”wrap”>’ . $e->outertext . ‘<div>’;

// Remove a element, set it’s outertext as an empty string
$e->outertext = ”;

// Append a element
$e->outertext = $e->outertext . ‘<div>foo<div>’;

// Insert a element
$e->outertext = ‘<div>foo<div>’ . $e->outertext;

How to traverse the DOM tree?

Background Konwledge:

// If you are not so familiar with HTML DOM, check this link to learn more…

// Example
echo $html->find(“#div1”, 0)->children(1)->children(1)->children(2)->id;
// or
echo $html->getElementById(“div1”)->childNodes(1)->childNodes(1)->childNodes(2)->getAttribute(‘id’);

Traverse the DOM tree:

You can also call methods with Camel naming convertions.

Method	Description
mixed $e->children ( [int $index] )	Returns the Nth child object if index is set, otherwise return anarray of children.
element $e->parent ()	Returns the parent of element.
element $e->first_child ()	Returns the first child of element, or null if not found.
element $e->last_child ()	Returns the last child of element, or null if not found.
element $e->next_sibling ()	Returns the next sibling of element, or null if not found.
element $e->prev_sibling ()	Returns the previous sibling of element, or null if not found.

How to dump contents of DOM object?

Quick way:

// Dumps the internal DOM tree back into string
$str = $html;

// Print it!
echo $html;

Object-oriented way:

// Dumps the internal DOM tree back into string
$str = $html->save();

// Dumps the internal DOM tree back into a file
$html->save(‘result.htm’);

How to customize the parsing behavior?

Callback function

// Write a function with parameter “$element”
function my_callback($element) {
// Hide all <b> tags
if ($element->tag==’b’)
$element->outertext = ”;
}

// Register the callback function with it’s function name
$html->set_callback(‘my_callback’);

// Callback function will be invoked while dumping
echo $html;

——————————————————更多资料请参看官方网站——————————————————

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