标签：jquery源码
no1：
// Define a local copy of jQuery
var jQuery = function( selector, context ) {
// The jQuery object is actually just the init constructor ‘enhanced‘
return new jQuery.fn.init( selector, context, rootjQuery ); //调用第二步init方法
},
no2：
jQuery.fn = jQuery.prototype = {
constructor: jQuery,
init: function( selector, context, rootjQuery ) {
var match, elem, ret, doc;
// Handle $(""), $(null), or $(undefined)
if ( !selector ) {
return this;
}
// Handle $(DOMElement)
if ( selector.nodeType ) {
this.context = this[0] = selector;
this.length = 1;
return this;
}
// The body element only exists once, optimize finding it
if ( selector === "body" && !context && document.body ) {
this.context = document;
this[0] = document.body;
this.selector = selector;
this.length = 1;
return this;
}
// Handle HTML strings
if ( typeof selector === "string" ) {
// Are we dealing with HTML string or an ID?
if ( selector.charAt(0) === "<" && selector.charAt( selector.length - 1 ) === ">" && selector.length >= 3 ) {
// Assume that strings that start and end with <> are HTML and skip the regex check
match = [ null, selector, null ];
} else {
match = quickExpr.exec( selector );
}
// Verify a match, and that no context was specified for #id
if ( match && (match[1] || !context) ) {
// HANDLE: $(html) -> $(array)
if ( match[1] ) {
context = context instanceof jQuery ? context[0] : context;
doc = ( context ? context.ownerDocument || context : document );
// If a single string is passed in and it‘s a single tag
// just do a createElement and skip the rest
ret = rsingleTag.exec( selector );
if ( ret ) {
if ( jQuery.isPlainObject( context ) ) {
selector = [ document.createElement( ret[1] ) ];
jQuery.fn.attr.call( selector, context, true );
} else {
selector = [ doc.createElement( ret[1] ) ];
}
} else {
ret = jQuery.buildFragment( [ match[1] ], [ doc ] );
selector = ( ret.cacheable ? jQuery.clone(ret.fragment) : ret.fragment ).childNodes;
}
return jQuery.merge( this, selector );
// HANDLE: $("#id")
} else {
elem = document.getElementById( match[2] );
// Check parentNode to catch when Blackberry 4.6 returns
// nodes that are no longer in the document #6963
if ( elem && elem.parentNode ) {
// Handle the case where IE and Opera return items
// by name instead of ID
if ( elem.id !== match[2] ) {
return rootjQuery.find( selector );
}
// Otherwise, we inject the element directly into the jQuery object
this.length = 1;
this[0] = elem;
}
this.context = document;
this.selector = selector;
return this;
}
// HANDLE: $(expr, $(...))
} else if ( !context || context.jquery ) {
return ( context || rootjQuery ).find( selector );
// HANDLE: $(expr, context)
// (which is just equivalent to: $(context).find(expr)
} else {
return this.constructor( context ).find( selector );
}
// HANDLE: $(function)
// Shortcut for document ready
} else if ( jQuery.isFunction( selector ) ) {
return rootjQuery.ready( selector );
}
if ( selector.selector !== undefined ) {
this.selector = selector.selector;
this.context = selector.context;
}
return jQuery.makeArray( selector, this );
},
// Start with an empty selector
selector: "",
// The current version of jQuery being used
jquery: "1.7.1",
// The default length of a jQuery object is 0
length: 0,
// The number of elements contained in the matched element set
size: function() {
return this.length;
},
toArray: function() {
return slice.call( this, 0 );
},
// Get the Nth element in the matched element set OR
// Get the whole matched element set as a clean array
get: function( num ) {
return num == null ?
// Return a ‘clean‘ array
this.toArray() :
// Return just the object
( num < 0 ? this[ this.length + num ] : this[ num ] );
},
// Take an array of elements and push it onto the stack
// (returning the new matched element set)
pushStack: function( elems, name, selector ) {
// Build a new jQuery matched element set
var ret = this.constructor();
if ( jQuery.isArray( elems ) ) {
push.apply( ret, elems );
} else {
jQuery.merge( ret, elems );
}
// Add the old object onto the stack (as a reference)
ret.prevObject = this;
ret.context = this.context;
if ( name === "find" ) {
ret.selector = this.selector + ( this.selector ? " " : "" ) + selector;
} else if ( name ) {
ret.selector = this.selector + "." + name + "(" + selector + ")";
}
// Return the newly-formed element set
return ret;
},
// Execute a callback for every element in the matched set.
// (You can seed the arguments with an array of args, but this is
// only used internally.)
each: function( callback, args ) {
return jQuery.each( this, callback, args );
},
ready: function( fn ) {
// Attach the listeners
jQuery.bindReady();
// Add the callback
readyList.add( fn );
return this;
},
eq: function( i ) {
i = +i;
return i === -1 ?
this.slice( i ) :
this.slice( i, i + 1 );
},
first: function() {
return this.eq( 0 );
},
last: function() {
return this.eq( -1 );
},
slice: function() {
return this.pushStack( slice.apply( this, arguments ),
"slice", slice.call(arguments).join(",") );
},
map: function( callback ) {
return this.pushStack( jQuery.map(this, function( elem, i ) {
return callback.call( elem, i, elem );
}));
},
end: function() {
return this.prevObject || this.constructor(null);
},
// For internal use only.
// Behaves like an Array‘s method, not like a jQuery method.
push: push,
sort: [].sort,
splice: [].splice
};
no3: 进入append入口
jQuery.fn.extend({
//buildFragment 方法
jQuery.buildFragment = function( args, nodes, scripts ) {
var fragment, cacheable, cacheresults, doc,
first = args[ 0 ];
// nodes may contain either an explicit document object,
// a jQuery collection or context object.
// If nodes[0] contains a valid object to assign to doc
if ( nodes && nodes[0] ) {
doc = nodes[0].ownerDocument || nodes[0];
}
// Ensure that an attr object doesn‘t incorrectly stand in as a document object
// Chrome and Firefox seem to allow this to occur and will throw exception
// Fixes #8950
if ( !doc.createDocumentFragment ) {
doc = document;
}
// Only cache "small" (1/2 KB) HTML strings that are associated with the main document
// Cloning options loses the selected state, so don‘t cache them
// IE 6 doesn‘t like it when you put <object> or <embed> elements in a fragment
// Also, WebKit does not clone ‘checked‘ attributes on cloneNode, so don‘t cache
// Lastly, IE6,7,8 will not correctly reuse cached fragments that were created from unknown elems #10501
if ( args.length === 1 && typeof first === "string" && first.length < 512 && doc === document &&
first.charAt(0) === "<" && !rnocache.test( first ) &&
(jQuery.support.checkClone || !rchecked.test( first )) &&
(jQuery.support.html5Clone || !rnoshimcache.test( first )) ) {
cacheable = true;
cacheresults = jQuery.fragments[ first ];
if ( cacheresults && cacheresults !== 1 ) {
fragment = cacheresults;
}
}
if ( !fragment ) {
fragment = doc.createDocumentFragment();
jQuery.clean( args, doc, fragment, scripts );
}
if ( cacheable ) {
jQuery.fragments[ first ] = cacheresults ? fragment : 1;
}
return { fragment: fragment, cacheable: cacheable };
};
标签：jquery源码
原文地址：http://blog.csdn.net/luozhonghua2014/article/details/46293465
