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这在下面来自jQuery latest的 init 函数中指的是什么

当从对象调用方法时，通常指的是持有该方法的对象。

但是在这种情况下，该方法是使用 new 关键字调用的。

这会改变 this 指向的内容还是仍然指向持有该方法的对象，在这种情况下，这将是 -jQuery.fn.init()

jQuery解构

jQuery 是这样全球化的：（第 9422 行）

window.jQuery = window.$ = jQuery;

jQuery 在这里定义：（第 42 行）

jQuery = function( selector, context ) {
    // The jQuery object is actually just the init constructor 'enhanced'
    return new jQuery.fn.init( selector, context, rootjQuery );
},

jQuery.fn.init 在这里定义：（第 95 行）

jQuery.fn = jQuery.prototype = {
    constructor: jQuery,
    init: function( selector, context, rootjQuery ) {
        var match, elem, ret, doc;

        // Handle $(""), $(null), $(undefined), $(false)
        if ( !selector ) {
            return this;
        }

        // Handle $(DOMElement)
        if ( selector.nodeType ) {
            this.context = this[0] = selector;
            this.length = 1;
            return this;
        }

        // Handle HTML strings
        if ( typeof selector === "string" ) {
            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 = rquickExpr.exec( selector );
            }

            // Match html or make sure no context is specified for #id
            if ( match && (match[1] || !context) ) {

                // HANDLE: $(html) -> $(array)
                if ( match[1] ) {
                    context = context instanceof jQuery ? context[0] : context;
                    doc = ( context && context.nodeType ? context.ownerDocument || context : document );

                    // scripts is true for back-compat
                    selector = jQuery.parseHTML( match[1], doc, true );
                    if ( rsingleTag.test( match[1] ) && jQuery.isPlainObject( context ) ) {
                        this.attr.call( selector, context, true );
                    }

                    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 );
    },

makeArray 在这里定义：（第 637 行） // 不用于 id 的基本选择

makeArray: function( arr, results ) {
    var type,
        ret = results || [];

    if ( arr != null ) {
        // The window, strings (and functions) also have 'length'
        // Tweaked logic slightly to handle Blackberry 4.7 RegExp issues #6930
        type = jQuery.type( arr );

        if ( arr.length == null || type === "string" || type === "function" || type === "regexp" || jQuery.isWindow( arr ) ) {
            core_push.call( ret, arr );
        } else {
            jQuery.merge( ret, arr );
        }
    }

    return ret;
},
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1 回答 1

3

当使用 调用函数时new，this总是引用新创建的对象实例。在这种情况下，函数恰好是表达式中的对象属性值并不重要.。

于 2012-09-24T22:46:31.177 回答