I am using this jquery popup plugin from this link on my WordPress site. It's working fine on all browsers but giving the following error on IE11.
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2@JohnDoe, can you provide a working example? – Dekel Aug 15 '16 at 02:11
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2@pragya, please put your some code so we can judge what is issue... my be it's is issue with dom element not found or have same id multiple time on page. – Haresh Vidja Aug 16 '16 at 14:23
11 Answers
As others have mentioned, the Object.assign() method is not supported in IE, but there is a polyfill available, just include it "before" your plugin declaration:
if (typeof Object.assign != 'function') {
Object.assign = function(target) {
'use strict';
if (target == null) {
throw new TypeError('Cannot convert undefined or null to object');
}
target = Object(target);
for (var index = 1; index < arguments.length; index++) {
var source = arguments[index];
if (source != null) {
for (var key in source) {
if (Object.prototype.hasOwnProperty.call(source, key)) {
target[key] = source[key];
}
}
}
}
return target;
};
}
From https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/assign
Test page: http://jsbin.com/pimixel/edit?html,js,output (just remove the polyfill to get the same error you're getting on your page).

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1Thank you! This works beautifully. I was having this exact problem with the Facebook Customer Chat widget, and applying this code just before FB's code did the trick. (For the one client who still insists upon using IE even though the rest of the world has moved on) – Alex Russell May 14 '19 at 15:20
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Something similar is available here https://www.npmjs.com/package/es6-object-assign -- I added it with npm install... and copied the automatic polyfill as suggested by `` – May 14 '20 at 10:06
@John Doe
I figured out from your comment that you want to implement this in node/react stack. This is very different from original question and you should have asked your own ;)
Anyways, Heres what you need to do...
You can use [es6-object-assign][1]. It is an ES6 Object.assign() "polyfill".
First, in package.json
in your root folder, add es6-object-assign
as a dependency:
"dependencies": {
"es6-object-assign": "^1.0.2",
"react": "^0.12.0",
...
},
Then if you want to use it in node environment use:
require('es6-object-assign').polyfill();
If you are having the issue on front (browser) end...
Add it in your index.html file...
<script src="location_of_node_modules/es6-object-assign/dist/object-assign.min.js"></script>
<script>
window.ObjectAssign.polyfill();
</script>
location_of_node_modules
depends on boilerplate you use, mostly just node_modules
, but sometimes when index.html is in a subdirectory you need to use, ../node_modules
As per the documentation, Object.assign() is a new technology, part of the ECMAScript 2015 (ES6) standard:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/assign
And it is not supported by IE.

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How do you implement a polyfill like https://www.npmjs.com/package/event-source-polyfill? In a node/react stack? – John Doe Aug 16 '16 at 04:08
A possible solution for this problem:
Add the script legacy.min.js before the custombox.min.js
source: custombox github project

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@Andres-Ilich has the right answer to your question but you're asking the wrong question:
Why not just use a jQuery plugin that supports IE like Zurb's excellent Reveal: https://github.com/zurb/reveal
It will do everything you want and not throw this error.

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Currently working on a jQuery popup myself: https://github.com/seahorsepip/jPopup
Has everything you'd expect of a popup and more :D
Anyway back on topic, I'm currently writing version 2 which is a big rewrite and adds support for IE6 (version 1 was IE7+) and ran into a similiar error...
Original code that gave the error in IE6:
//Insane code for an insane browser
this._vars.fakeScrollbar = $("<div style=\"position:absolute;top:expression(document.documentElement.scrollTop);right:0;bottom:0;margin-left:-200px;width:0;overflow-y:scroll;height:expression(document.documentElement.clientHeight);z-index:9999999;\"></div>");
The hack I had to come up with:
//Insane code for an insane browser
this._vars.fakeScrollbar = $("<div>");
this._vars.fakeScrollbar.html("<div style=\"position:absolute;top:expression(document.documentElement.scrollTop);right:0;bottom:0;margin-left:-200px;width:0;overflow-y:scroll;height:expression(document.documentElement.clientHeight);z-index:9999999;\"></div>");
this._vars.fakeScrollbar = this._vars.fakeScrollbar.children();

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Since you tagged the question with jQuery you can use the jQuery extend function. No need for a polyfill and it does deep merge as well.
For Example:
var object1 = {
apple: 0,
banana: { weight: 52, price: 100 },
cherry: 97
};
var object2 = {
banana: { price: 200 },
durian: 100
};
// Merge object2 into object1
$.extend( object1, object2 );
Result:
{"apple":0,"banana":{"price":200},"cherry":97,"durian":100}

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please add script
<script src="https://cdn.jsdelivr.net/npm/es6-object-assign@1.1.0/dist/object-assign-auto.min.js"></script>
to html file to resolved this problem.

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These error usually occurs when some html element id has the same id as some variable in the JavaScript function. After changing the name of one of them code worked.
Source : SCRIPT438: Object doesn't support property or method IE
Other link : jquery validation IE Object doesn't support property
Basically, Object.assign
isn't supported by all browsers, however, it's possible to re-assign it at Object
case it's not supported by the current browser.
It's pratice to make a polyfill function, which behaves in the same way as Object.assign(target, ...)
of ES6.
I think the best solution is to iterate each argument after target
, assign each property of arguments
objects to target
, considering a iteration between objects and arrays, to avoid creating references. Optionally, to not lost instances, you can detect if the last instance of the property is only equal to "Array"
or "Object"
, and doing so you won't lost a Image
interface (e.g) if you plan to create new references, but objects with these instances will still be reference.
Edit: the original Object.assign
doesn't work in this way.
According to this solution, I've my own polyfill which can be found here.

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React solution for IE11
Regarding shramee's answer, which stated something like this:
@JohnDoe from your comment, you want to implement this in node/react stack. This is very different from the original question, but you might use es6-object-assign, an ES6
Object.assign()
"polyfill":
This polyfill was updated and things can be done a bit differently now:
in
package.json
in your root folder, addes6-object-assign
as a dependency (executingnpm i
in a command line after):"dependencies": { "es6-object-assign": "^1.0.2", "react": "^16.8.6", ... },
Or simply run:
npm i --save es6-object-assign
To use it in a node environment:
require('es6-object-assign').polyfill(); // Same version with automatic polyfilling require('es6-object-assign/auto');
To use it in your index.html, just add the automatic polyfill JS file reference to it (if you have scripts in the
<body>
that invokeObject.assign()
you may add it at the end of the<head>
element).Invoking directly from
node_modules
:<script src="location_of_node_modules/es6-object-assign/dist/object-assign-auto.min.js"></script>
location_of_node_modules
depends on your project structure (when index.html is in a subdirectory you might need:../node_modules
).However, this might have not worked for you (due to
node_modules
folders access, e.g. you are using create-react-app). If so, just copy the JS file from thedist/
node_modules folder to thepublic/
folder and then:<script src="%PUBLIC_URL%/object-assign-auto.js"></script>
You might want to use the non-minified file and add other customized polyfills (e.g.
startsWith
).

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