Complete comments of jQuery1.0 source code analysis Constructor (5)

 

JQuery's function design is very compact and there are many calls to each other. For example, you need to understand function a and find that function B is called in function a, and Function c is called in function B. In this way, the system will basically be dizzy.

 

Therefore, I suggest reading a function and a function. Do not follow it up. After reading all the articles, you will naturally get through.

 

 

So today I will annotate jQuery constructor.

 

 

Function jQuery (a, c ){

 

// Process the ready function, $ (function (){})

If (a & a. constructor = Function & jQuery. fn. ready)

Return jQuery (document). ready ();

 

// Set a default value for

A = a | jQuery. context | document;

 

// If a is a jQuery object, merge a and null arrays and return the result. The purpose of this operation is not to destroy the original jQuery object.

// (Note: The jquery attribute is available for each jQuery object and its value is the jQuery version)

If (a. jquery)

Return $ (jQuery. merge (a, []);

 

// If c is a jQuery object, call the find function to find

If (c & c. jquery)

Return $ (c). find ();

// None of the above cases. Start the new jQuery object.

If (window = this)

Return new jQuery (a, c );

 

// If a is an html code, $ ('<div/>') converts the html code into a Dom element.

// JQuery. clean converts html code into a Dom element array.

Var m =/^ [^ <] * (<. +>) [^>] * $/. exec ();

If (m) a = jQuery. clean ([m [1]);

 

// If array a is an array or an array of classes containing dom elements, merge array a and null.

// In other cases, call the find function. The find function is used to process css expressions.

// Call the get method to return the jQuery object.

This. get (a. constructor = Array | a. length &&! A. nodeType & a [0]! = Undefined & a [0]. nodeType?

// Assume that it is an array of DOM Elements

JQuery. merge (a, []):

 

// Find the matching elements and save them for later

JQuery. find (a, c ));

 

// Check whether the last parameter is a Function. If yes, traverse and execute it.

Var fn = arguments [arguments. length-1];

If (fn & fn. constructor = Function)

This. each (fn );

}

 

Finally, from the above constructor code, jQuery constructor mainly supports the following methods:

 

 

1. $ (Function), ready Function

 

2. $ (Element)/$ ([Element]) can directly convert Dom elements or arrays into jQuery objects.

3. $ (CSS Expression, Content). You can also use CSS expressions to select Dom elements.

 

4. $ (Html) and html can also be converted to jQuery objects.

 

 

Author: baozhifei