QueryPath (QP) library implements effects similar to jQuery in PHP. It can also be used to easily process XML HTML... It’s so powerful! ! !

A QueryPath Tutorial(A simple explanation)
QueryPath makes use of method chaining to provide a concise suite of tools for manipulating a DOM.
The basic principle of method chaining is that each method returns an object upon which additional methods can be called . In our case, the QueryPath object usually returns itself.
Let's take a look at an example to illustrate:
$qp = qp(QueryPath::HTML_STUB); // Generate a new QueryPath object.(Create a QP object)
$qp2 = $qp->find('body'); // Find the body tag.(Find the "body" tag)
// Now the surprising part: (Please see what surprises you below)
if ( $qp === $qp2) {
// This will always get printed.(It will always be output like this)
print "MATCH";
}
Why does $qp always equal $qp2? Because the find() function does all of its data gathering and then returns the QueryPath object.
This might seem esoteric, but it all has a very practical rationale. With this sort of interface, we can chain lots of methods together:
(You can do the same with jQuery
qp(QueryPath::HTML_STUB)->find('body')->text('Hello World')->writeHTML();
In this example, we have four method calls:
qp(QueryPath::HTML_STUB): Create a new QueryPath object and provide it with a stub of an HTML document. This returns the QueryPath object.
find('body'): This searches the QueryPath document looking for an element named 'body '. That element is, of course, the portion of the HTML document. When it finds the body element, it keeps an internal pointer to that element, and it returns the QueryPath object (which is now wrapping the body element).
text('Hello World'): This function takes the current element(s) wrapped by QueryPath and adds the text Hello World. As you have probably guessed, it, too, returns a QueryPath object. The object will still be pointing to the body element.
writeHTML(): The writeHTML() function prints out the entire document. This is used to send the HTML back to the client. You'll never guess what this function returns. Okay , you guessed it. QueryPath.
So at the end of the chain above, we would have created a document that looks something like this:

Copy the code as follows:



 

This is a test page

Test text

Now you should have an idea of how QueryPath works. Grab a copy of the library and try it out! Along with the source code, you will get a nice bundle of HTML files that cover every single public function in the QueryPath library (no kidding). There are more examples there, too. 
不错的东东！赶紧 Grab 它吧~~！

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