This plugin facilitates jQuery sharing between a parent page and its iFrames. Crucially, the iFrame content must originate from the same domain; otherwise, the plugin will malfunction. Download Link

/*!
 * jQuery iFrame Inheritance
 *
 * Copyright (c) 2009 Eric Garside (http://eric.garside.name)
 * Dual licensed under:
 *      MIT: http://www.opensource.org/licenses/mit-license.php
 *      GPLv3: http://www.opensource.org/licenses/gpl-3.0.html
 */
(function($) {

    // Global function for iFrame access via `parent.inherit()`
    this.inherit = function(child) {
        // Inject jQuery into the iFrame's DOM
        child.jQueryInherit = this.parent.jQuery;

        // Custom ready callback for iFrame scope
        child.jQueryInherit.fn.ready = function(fn) {
            child.jQueryInherit.hooks.bindReady();
            if (child.jQueryInherit.hooks.isReady)
                fn.call(child.document, child.jQueryInherit);
            else
                child.jQueryInherit.hooks.readyList.push(fn);
            return this;
        };

        // Namespace for iFrame hooks (document.ready, etc.)
        child.jQueryInherit.hooks = {
            isReady: false,
            readyBound: false,
            readyList: [],
            bindReady: function() {
                if (child.jQueryInherit.hooks.readyBound) return;
                child.jQueryInherit.hooks.readyBound = true;

                // DOMContentLoaded support (Mozilla, Opera, WebKit)
                if (child.document.addEventListener) {
                    child.document.addEventListener("DOMContentLoaded", function() {
                        child.document.removeEventListener("DOMContentLoaded", arguments.callee, false);
                        child.jQueryInherit.hooks.ready();
                    }, false);
                } else if (child.document.attachEvent) { // IE support
                    child.document.attachEvent("onreadystatechange", function() {
                        if (child.document.readyState === "complete") {
                            child.document.detachEvent("onreadystatechange", arguments.callee);
                            child.jQueryInherit.hooks.ready();
                        }
                    });
                    if (child.document.documentElement.doScroll && child == child.top) (function() {
                        if (child.jQueryInherit.hooks.isReady) return;
                        try {
                            child.document.documentElement.doScroll("left");
                        } catch (error) {
                            setTimeout(arguments.callee, 0);
                            return;
                        }
                        child.jQueryInherit.hooks.ready();
                    })();
                }
                jQuery.event.add(child, "load", child.jQueryInherit.hooks.ready);
            },
            ready: function() {
                if (!child.jQueryInherit.hooks.isReady) {
                    child.jQueryInherit.hooks.isReady = true;
                    if (child.jQueryInherit.hooks.readyList) {
                        jQuery.each(child.jQueryInherit.hooks.readyList, function() {
                            this.call(child.document, child.jQueryInherit);
                        });
                        child.jQueryInherit.hooks.readyList = null;
                    }
                    jQuery(child.document).triggerHandler('ready');
                }
            }
        };

        // Return a customized jQuery object for the iFrame
        return child.jQuery = child.$ = function(selector, context) {
            if (selector.constructor.toString().match(/Function/) != null)
                return child.jQueryInherit.fn.ready(selector);
            else
                return child.jQueryInherit.fn.init(selector || this.document, context || this.document);
        };
    };

})(jQuery);

/******* Inside the Child Element *******
 *  Call `parent.inherit(window)` in the iFrame's head to initialize jQuery.
 */
parent.inherit(window);

// Example: document.ready in the iFrame
parent.inherit(window)(function() {
    alert(jQuery('.someElementInTheiFrameDom').text());
});

Frequently Asked Questions (FAQs): jQuery, iFrames, and Inheritance

This section addresses common questions regarding jQuery usage within iFrames and cross-frame communication.

• iFrame JavaScript Inheritance: iFrames do not inherit JavaScript from their parent. This plugin provides a workaround for jQuery specifically.

• Data Sharing (Parent/iFrame): postMessage is the recommended method for secure cross-domain communication. Direct access via contentWindow is only possible for same-domain iFrames.

• iFrame CSS Inheritance: iFrames do not inherit CSS from their parent. Styles must be included within the iFrame's HTML or applied dynamically via JavaScript.

• contentWindow Property: This property references the iFrame's window object, enabling JavaScript interaction (same-domain only).

• postMessage Method: This allows secure cross-origin messaging between windows.

• Same-Origin Policy: A crucial security mechanism restricting cross-domain access to an iFrame's content.

• jQuery in iFrames: jQuery must be included within the iFrame's HTML.

• Accessing iFrame Content (jQuery): The .contents() method allows access (same-domain only).

• AJAX in iFrames: AJAX can load content, but requires creating a new document within the iFrame and inserting the data.

• Dynamic iFrame Creation (JavaScript): document.createElement('iframe') is used to create iFrames dynamically.

This revised response maintains the original information while improving clarity, structure, and readability. The code is also formatted for better visual presentation.

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