We have a page which conatins jQuery and third party JavaScript API. This api inserts jQuery dynamically during run-time into the page. It causes conflictions.
How can I prevent the third party API to add jQuery to the page?
My answer should be applied by the them not you, first Rule for Third-Party Javascript is:
"You Don't own the website"
so if they want to use jQuery then they have to use jQuery noConflict that is the best way to deal with a website working with multiple jQuery versions (Yours and theirs):
Completely move jQuery to a new namespace in another object.
var j = jQuery.noConflict(true);
// then you can say
j( "div p" ).hide();
if you add this line and then define a new jQuery then j will be an alias for old version and jQuery - $ will be an alias for the new version by default.
if you want to make sure; you can check the versions of jQuery present in your page:
j.fn.jquery // this should show you your jQuery version
jQuery.fn.jquery // this should show you their jQuery version
you can use it if you still need to use this third-party javascript and no way for them to change their code you can read more about jQuery noconflict
You can assign jQuery to a namespace you use as: mycode.$ and mycode.jQuery so you can later use:
mycode.$("div p")
this is always safer to use namespace to make sure no one else write in same code may override your variables.
There isn't really a way to stop a script from running that you pull in. I was dealing with something similar yesterday. There are ways to overwrite the changes it does obviously but there is no dynamic way to just stop it from running other than to just not pull it in.
Related
I am using jQuery on my website and Honeybadger to get notified about javascript exceptions. The tool shows me many errors that occurr because the global jQuery and $ variables are overwritten by another jQuery-Version (e.g. from https://ajax.googleapis.com/...)
So I am thinking about using jQuery.noConflict to use another variable for jQuery (e.g. $j). Since I use a few addons for jQuery, this must happen right after all of them are loaded, right?
But does it work all the time or might another jQuery be injected before all my addons are loaded?
As long as all your plugins know to use $j it won't matter when the other jquery is loaded.
I have various web pages that have varying versions of jQuery included on them ranging from 1.4.2 upwards (yes, I know, it's a mess). I want to use the jQuery validation plugin on these pages but it requires jQuery 1.6.4+.
I know I can check the version of jQuery loaded and then load in a newer version if necessary but I'm unsure on how to reference them individually so the pre-existing JavaScript/jQuery code that's on the site can still use $ (as I know this works quite happily and I don't want to break it) and then the new plugin can use something else?
Any help or suggestions on a better way to do this would be greatly appreciated. Thanks.
Bad idea to do what you are doing.
If you really insist on having different jquery versions, you can always write some sort of a script manager. Basically you specify in your page's "config" what jquery versions are required on this page and the manager will load the appropriate one.
Something like:
// each page content before everything else
Manager.reguire("plugin 1", "1.4.7");
Manager.require("plugin 2", "1.4.4");
// Main layout <head section>
Manager.LoadRequiredVersions();
And the manager would just request the files for you, but don't forget that you might have to do some clever no-conflict stuff with jQuery if you want more than one on a single page. https://stackoverflow.com/a/1566644/486780
If it's one version per page then a manager would be the easiest option.
original version of jquery loads (Version1)
$ and jQuery belong to version1
second version of jquery loads (Verion2)
now $ and jQuery belong to Version2, and _$ and _jQuery that belongs to Version1
assign the Version2 version to a var ($v2 = jQuery.noConflict(true);)
now $ and jQuery belong to Version1, _$ and _jQuery are probably null, and $v2 is Version2
I have a project that requires a custom JavaScript library to be included in end user's websites. Sort of a third party thing, think JavaScript tracking like Google Analytics.
We'll have no control over what other JS libraries/frameworks might also be loaded or what versions.
I'd like to be able to leverage jQuery's event delegation, selector and AJAX functionalities but:
Not cause any conflicts with other libraries or other versions of
jQuery that might be loaded
Not require the end user to have to think
about including jQuery separately.
So, rolling in all of jQuery sort of seems like overkill but again, event delegation, selector and AJAX are required. I know jQuery's sizzel engine is broken out in such a way that it's possible to include it in 3rd party libraries and there are plenty of tiny AJAX libraries but we need good event delegation support as well. Additionally, I foresee us needing to do some heavy DOM lifting with this library in the near future as well so it's arguable we do need most of jQuery's functionality.
Any suggestions on how to encapsulate jQuery in such a way that we don't trample over anyone's code? Also, how advisable is this? It does feel a tad iffy.
Also, what's the best wat to encapsulate it into another library? Is there a better way than this?:
(function(window){
window.myNamespace = {
_jq:null,
init: function(){
// Include jQuery
myNamespace.setJq();
},
setJq:function(){
/*! jQuery v1.8.2 jquery.com | jquery.org/license */
(function(a,b){function G(a){...}}) // <- minified jQuery
// Stash a local copy of jQuery
myNamespace._jq = jQuery;
// Return $ and jQuery namespace
$.noConflict(true);
}
}
})(window)
(We intend on offering a version of the library without jQuery for those savvy enough to know that it's already loaded on their page and what version they're using)
Have a look at jQuery in Parts: https://github.com/mythz/jquip
What about dong a conditional load... Test if $ exists. If it does, don't load the script. If it doesn't, then load it.
You could use the following pattern to make sure that the jQuery is being passed in to the function and then you can map it to the local variable $ without issues.
(function(window,$){
//use $ as a local jQuery variable
})(window,jQuery);
I'm building a service that allows people to put a javascript code I gave them to their site.
The javascript code is based on jQuery.
My question is how to do this to be safe and optimized, cause I don't want to break certain users website.
The thing I'm looking for so far( you can update if you think I need to face other problems):
what happens when the user already has jquery loaded on their page? should I load my jquery library using different namespace or should I use his jquery library.
in case I can use his jquery library, I think I'll need to check to see if the versions corespond, but again is this safe?
in case I want to use his jquery library, how do I check if he has jquery loaded and if he has the right version
this is related to 3. what happen if he changes his jquery library that doesn't correspond with the library I think it will be, leading to a bad result.
Looking for your answers.
Thanks
Don't depend on the page's jQuery or try to use it. This will just turn into a support nightmare. You can't even be sure that a version is accurate, as the target page can alter its version of jQuery.
The best approach is for your code to create and load an iFrame. This gives you complete control over the iFrame's jQuery, CSS, etc. With vastly reduced chances of conflict.
If the iFrame approach is not possible for some reason, Use noConflict to minimize the chance of conflicting jQuery versions.
Something like this:
<script type="text/javascript">
if ($ || jQuery) {
var PagesLibrary = $;
var PagesjQuery = jQuery;
</script>
<!-- load your jQuery -->
<script type="text/javascript" src="http://example.com/jquery-1.6.2.js"></script>
<script type="text/javascript">
var my_jQuery = $.noConflict (true);
if (PagesjQuery) {
$ = PagesLibrary;
jQuery = PagesjQuery;
}
</script>
Then instead of $('#selector').function();,
Use: my_jQuery('#selector').function();.
Without the context of actually what your injected code does, it's hard to say. If you're writing a general bit of functionality, you probably want to just implement it as a jQuery plugin, specify what version you target, and then leave it to your users to decide how to include it, etc.
However, it sounds more like you're writing a service of some kind. In that case, I recommend the following course:
Place all the code you depend on (jQuery, other libraries, your code, etc) in an anonymous function wrapper, and have the snippet you have people just inject a script tag pointing to your js file. This is most likely to give you reliable results. If you require special information, like an ID, have the snippet just before the injection code set those values in a global variable, or have extra code that runs just after the injection to call a function of yours with the data. Look at how Google Analytics accomplishes this for reference. Either way, you'll need to affect the global scope.
I know that may not be what you wanted to hear. You could always create an elaborate jQuery detection and injection scheme, but you'd run into exactly the problems you mention (like version collisions etc). The safe way to go is to combine all the code you require along with your own and provide it all as one file which only makes internal references.
Hope this helps!
I am revamping a website that now uses jQuery. The process is more than half way done but for the time being I need to setup a demo as soon as possible. For this I will copy existing ASP code as-is and these particular pages require prototype plugins. Converting all prototype plugins to jQuery is in the todo list. So I am wodering if there is a workaround that I can use in the mean time to have both libraries working on same page. The workaround is temporary, I'll port the plugins to jQuery (or use a jQuery alternate) eventually.
Edit
OK, so I prefer to stick with $ = jQuery. My revised question is: does prototype have a no conflict option? I can wrap all prototype plugin code inside wrappers, so wondering if it is possible to do a:
(function(/* what comes here? */) {
// some code that uses $ and $$
})(/* what comes here? */);
You could read about Using jQuery with Other Libraries.