jQuery物件初始化的傳參方式_jquery

jQuery物件初始化的傳參方式包括：

1.$(DOMElement)
2.$('

...

'), $('#id'), $('.class') 傳入字串, 這是最常見的形式, 這種傳參數經常也傳入第二個參數context指定上下文,其中context參數可以為$(...), DOMElement
3.$(function() {}); $(document).ready(function() { });
4.$({selector : '.class', context : context}) $('.class', context)

複製程式碼 程式碼如下:

jQuery.fn = jQuery.prototype = {
    constructor: jQuery,
    init: function( selector, context, rootjQuery ) {
        var match, elem, ret, doc;
        // 處理$(""), $(null), $(undefined), $(false)這幾種參數,直接回傳this
        if ( !selector ) {
            return this;
        }
        // 當傳參selector為DOM結點,將context置為selector
        if ( selector.nodeType ) {
            this.context = this[0] = selector;
            this.length = 1;
            return this;
        }
        // Handle HTML strings
        // 當傳入的selector參數為字串時,
        if ( typeof selector === "string" ) {
            if ( selector.charAt(0) === "" && 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: $(#id)
                } else {
                    elem = document.getElementById( match[2] );
                    // Check parentNode to catch when Blackberry 4.6 returns
                    // nodes that are no longer in the document #6963
                    if ( elem && elem.parentNode ) {
                        // 處理 IE 與 Opera 回復專案的狀況
                        // 以名稱而非 ID
                        if ( elem.id !== match[2] ) {
                            return rootjQuery.find( 選擇者 );
                        }
                        // 否則，且我們將元素直接注入 jQuery 物件中
                        this.length = 1;
                        this[0] = elem;
                    }
                    this.context = 文檔;
                    this.selector = 選擇者;
                    請使用此；
                }
            // 句柄：$(expr, $(...))
            } else if ( !context || context.jquery ) {
                return ( context || rootjQuery ).find( 選擇者 );
            // 句柄：$(expr, context)
            // （相當於：$(context).find(expr)
            } 其他 {
                return this.constructor( context ).find( 選擇者 );
            }
        // 句柄：$(function)
        // 文件準備好的捷徑
        // 當selector為function時相當於$(document).ready(selector);
        } else if ( jQuery.isFunction( 選擇器 ) ) {
            return rootjQuery.ready( 選擇者 );
        }
        //當selector參數為{selector:'#id', context:document}之類時，重置屬性selector和context
        if ( 選擇器.selector !== 未定義 ) {
            this.selector = 選擇者.selector;
            this.context = 選擇者.context;
        }
        return jQuery.makeArray( 選擇者, this );
    }
};

以上就是本文的全部內容了，希望大家能夠喜歡。