How to use jquery from parent inside an iframe?

问题:

I have a file, let us call it parent-win.html, served by domain example.com. This file has jquery included in it. An iframe, lets call it iframe-win.html, is embedded in this page. iframe-win.html has a form element with id form-elem and value Hello World!. Now I do following inside iframe.

var jQuery = parent.jQuery;
console.log(jQuery('#form-elem').val());

According to my limited knowledge of JS I should see Hello World! on console but instead I see undefined. Now, my question is do I need to load jquery again in an iframe or can I utilise jquery object already loaded in parent window?

Do note that this is not as usual access iframe/parent content from parent/iframe.

回答1:

try this in the iframe:

if (typeof(jQuery) == "undefined") {
    var iframeBody = document.getElementsByTagName("body")[0];
    var jQuery = function (selector) { return parent.jQuery(selector, iframeBody); };
    var $ = jQuery;
}

回答2:

Here is a better solution based on the Moin's answer:

if (typeof(jQuery) == "undefined") {
    window.jQuery = function (selector) { return parent.jQuery(selector, document); };
    jQuery = parent.$.extend(jQuery, parent.$);
    window.$ = jQuery;
}

So we can use $'s functions like $.get, $.extends, etc.

回答3:

You need to load jQuery inside the iframe.

EDIT: Okay, if the frame is not on the same domain, then you do not have to reload jQuery. See Access jQuery library from iframe