I have a site that relies heavily on JavaScript and uses jQuery throughout.
I'm not going to attempt to make the site work for those who don't have JavaScript enabled.
However, I would like to show a banner at the top of the page which tells them the site is intended for use with JavaScript enabled and perhaps a modern browser, etc.
I was thinking of just putting a PHP include on all pages that contains a <noscript> with the banner inside that. Is this is good approach or is there a better way?
<noscript> is the way to go.
You should also provide links to other, better browsers in the <noscript> tag if you can detect that's a browser without JavaScript.
If you wish to be more drastic about it, start with the markup <body class="nojs"> and, onload remove that class with JavaScript.
You could then have body.nojs #wrapper { display: none; }, body.nojs #notice { display: block } in your CSS.
Maybe How to know and handle disabled JavaScript in the browser can help you.
That is definitely one alternative...
Another is to have the banner visible by default without using noscript and then a $().ready() which hides the banner for all JavaScript enabled browsers.
Related
The NoScript browser plugin is getting increasingly popular. For those of us who run webpages which are heavily dependent on javascript, how can we check for presence of this plugin and alert the user with some sort of "always present" drop down bar at the top of the screen if so?
I actually just tried using NoScript on StackOverflow.com and saw that they do EXACTLY what I was thinking about! Is this just a simple browser check for javascript?
Open the source of a Stack Overflow page and look around.
You see that they are using <noscript>-tags to add additional content when no JavaScript is available.
A simple manual implementation would be to do something like this:
HTML:
<div id="requireJS">This site requires JS!</div>
Script:
var warning = document.getElementById('requireJS');
warning.parentNode.removeChild(warning);
This'll show the warning when JS is disabled, and remove it when JS is enabled.
Note: I'm not saying it's better than <noscript>, just that it could also be done this way.
Using Answer from agam360 in case somebody searches for the NoScript plugin again as I did.
How to detect if JavaScript is disabled?
And most specifically, the answer by Hairbo which seems like the best solution as I see it for already developed websites which do not have an elegent degradation: https://stackoverflow.com/a/3926750/646456
Actually I like the style approach so you can hide / unhide anything easily.
on default stylesheet :
.nojs { display:none;}
On layout html:
<noscript>
<style>
.nojs { display:block }
.container {display:none}
</style>
</noscript>
<div class="container">
this will show with js
</div>
<div class="nojs">
this will show without js
</div>
The essence of the problem is as follows:
There is a page, I need to modify the contents of the browser extensions, you can use jQuery.
Tried $(document).ready(), but then the contents are still displayed for a short period (FOUC). I can not make changes to the page styles on the server.
I'm using the kango framework to build the extension.
Using only ECMAscript, you can't reliably avoid it. You have like no shot if you wait for DOMContentLoaded event, because at that point the DOM is pretty much rendered and displayed (which is what you see for a short period).
Your best shot would be to modify the CSS as soon as possible. If the stylesheet definition gets loaded before the DOM gets rendered and you would have set like
body {
display: none;
}
you would not see anything. You could try like
<body>
<script>
document.body.style.display = 'none';
</script>
<!-- more html -->
</body>
if that is any viable / useable solution for you.
I suggest you to use a combination of CSS and JavaScript. I had the same issue using jQueryUI on a site I'm building and found that a lot of these solutions out there would make the content unavailable to those without JavaScript.
So, here is what I did:
CSS:
.flash #wrapper {
display: none;
}
This sets <div id="wrapper"> to hidden only if it is a decedent of the flash class. So, to keep it from being hidden from those without JavaScript I add the flash class to <html> element. So, it can only be physically hidden if an end-user has JavaScript enabled, otherwise they'll at least have access via the unstyled content.
JavaScript:
$('html').addClass('flash');
$(document).ready(function() {
/* Do all your stuff */
/* When done show the wrapper with the content styled */
$(#wrapper).show();
});
Depending on your pages time to load you might get a little flash, but it won't be a flash of unstyled content, which is rather ugly. In my case I had a jQueryUI menu item that would flash the normal <ul> element first then the menuUI item, and my <div> elements are resized with jQuery so that each <div> column is equal height, but it would flash the different heights first. This fixed it while still giving accessibility to non-JavaScript browsers.
I often find myself showing/hiding elements with jQuery, for example a simple tabbed content area where the first tab is visible and the others are not until they are displayed with the javascript. I know it's not good practice to hide the initially hidden ones using CSS (display: none) and then showing the correct ones with JS as non-JS users will never see a thing. So by default I show all and then hide the relevant ones with JS.
In doing this though, the hidden elements will load and then only hide when document is ready. How can I stop this happening? Is there a way of doing this in a way that will degrade gracefully but also not have elements appearing whilst loading, and then promptly disappearing as this looks a bit shoddy.
Unfortunately, the way that Javascript works, this doesn't seem to be possible. There will always be a fraction of a second between the first rendered frame and by the time the JavaScript to hide the element gets executed I was wrong about that, jQuery seems to be able to do that. So, CSS is the best means for this. Luckily, you can add an alternate CSS stylesheet within an infamous <noscript> tag:
<style type="text/css">
#jquery-thing {
display: none;
}
</style>
<noscript>
<style type="text/css">
#jquery-thing {
display: block !important;
}
</style>
</noscript>
Here's the JSFiddle link:
http://jsfiddle.net/kylewlacy/dbWuc/
a few thoughts...
If you don't mind jQuery being littered all over the page as opposed to being all in a separate file, you can call $('#divToHide').hide(); immediately after the element appears. Not very good practice though. Although it depends on the use case, if you are largely a designer/themer creating a 5 page brochure site, you should choose what is right for you!
Or if you're a bit more of a techie, you might like to mess around with .live()/.livequery() and catch the element's insertion with JS and hide is straight away. See this post Is there a jquery event that fires when a new node is inserted into the dom?
My application depends on JavaScript, I want to check the client browser's JavaScript is enabled or not and raise an alert message if its turned off.
There's actually a <noscript> tag that you can use to display the content contained inside when javascript is not available.
Something like:
<noscript>
<div>
You must enable javascript to continue.
</div>
</noscript>
The div just won't show if they have javascript, and it's pretty easy to tell if javascript IS working, no matter whether you need it to ping your server back to let it know, or use it to perform some more advanced functions.
Put the message in a <div> that's wrapped in a <noscript> tag. If JavaScript is disabled, the <div> will be rendered as part of the DOM; if script is enabled, the div won't be in the DOM.
For example, you can put the following immediately after the opening <body> tag, and style it through CSS to have red background to make it more prominent.
<noscript>
<div id="js-warning">
To be able to access all of our features, you need a browser that supports JavaScript, and it needs to be enabled.
</div>
</noscript>
"Raise an alert message if its turned off" is paradox, since if it is turned off, you cannot "do" anything programatically.
You can do it the other way 'round, however: make that message appear by default, and have JavaScript hide it if it is turned on (e.g. by setting a DIVs visibility to hidden),
or you rely on the standard compliance of the browser and use the <noscript> tag. Stuff inside the <noscript> gets shown if no javascript is enabled. BTW, make sure to set the type="text/javascript" attribute of the script tag.
See also http://www.w3.org/TR/REC-html40/interact/scripts.html#h-18.3
A browser may be "JavaScript capable" but that does not mean that JavaScript has not been disabled by the user or by an admin. There is no real way to determine this. Best practices dictate "Progressive Enhancement"; that is, you application needs to work without JavaScript first - then add the JavaScript functionality for those (most) that have it enabled.
http://www.alistapart.com/articles/progressiveenhancementwithjavascript/
http://www.webcredible.co.uk/user-friendly-resources/dom-scripting/progressive-enhancement.shtml
Avoid hacky solutions to this and bear in mind that there are also accessibility issues for people with screen readers. <noscript> content only displays if JavaScript is disabled. Most screen reader users have JavaScript enabled, so they will see your inaccessible script rather than the <noscript> content.
I found some good cons here:
The noscript element only detects whether the browser has JavaScript enabled or not. If JavaScript is disabled in the Firewall rather than in the browser then the JavaScript will not run and the content of the noscript element will not be displayed.
Many scripts are dependent on a specific feature or features of the language being supported in order for them to be able to run (for example document.getElementById). Where the required features are not supported the JavaScript is unable to run but since JavaScript itself is supported the noscript content will not be displayed.
The most useful place to use the noscript element is in the head of the page where it would be able to selectively determine what stylesheet and meta elements get applied to the page as the page is loading rather than having to wait until the page is loaded. Unfortunately the noscript element is only valid within the body of the page and so cannot be used in the head.
The noscript element is a block level element and therefore can only be used to display entire blocks of content when JavaScript is disabled. It cannot be used inline.
Ideally, web pages should use HTML for the content, CSS for the appearance, and JavaScript for the behavior. Using the noscript element is applying a behavior from within the HTML rather than applying it from JavaScript.
Source: http://javascript.about.com/od/reference/a/noscriptnomore.htm
I very much agree on last point. Is there a way to make and add an external <noscript> file? Should we place <noscript> in the <head>?
It's better to have the default be non-javascript, and then let a javascript code overwrite with a javascript enabled page. Doesn't have to be much. Can just be a display:none; block, which is then set to display:block; by javascript, and vice versa for the non-js page.
After pondering for many days and changing my code back and forth, I think I have clearer picture now and would like to share my two cents worth on the subject before I forget.
<div id='noscript'>show non-js content</div>
<script>document.getElementById('noscript').style.display='none';</script>
<script id='required script'>show js content</script>
vs
<noscript>show non-js content</noscript>
<script id='required script'>//show js content</script>
Depending on the situation, there are three cases for consideration:
Case 1 - If required script is inline
JavaScript disabled
Content in <noscript> element appears immediately, non-js content is
shown
Content in <div> element appears immediately, non-js content is shown
JavaScript enabled
Content in <noscript> element does not appear at all, js content shown
Content in <div> element may momentarily appear before being hidden, js
content shown
For this case, using <noscript> element is advantageous.
Case 2 - If required script is from external (third-party) source, but hiding of <div> element is done with inline script
JavaScript disabled
Content in <noscript> element appears immediately, non-js content is
shown
Content in <div> element appears immediately, non-js content is shown
JavaScript enabled but required script is blocked
Content in <noscript> element does not appear at all, nothing is shown!
Content in <div> element may momentarily appear before being hidden, nothing is shown!
JavaScript enabled and required script is received
Content in <noscript> element does not appear at all, js content shown
Content in <div> element may momentarily appear before being hidden, js
content shown
For this case, using <noscript> element is advantageous.
Case 3 - If required script hides the <div> element
JavaScript disabled
Content in <noscript> element appears immediately, non-js content is
shown
Content in <div> element appears immediately, non-js content is shown
JavaScript enabled but required script is blocked
Content in <noscript> element does not appear at all, nothing is shown!
Content in <div> element appears, non-js content is shown
JavaScript enabled and required script is received
Content in <noscript> element does not appear at all, js content shown
Content in <div> element may momentarily appear before being hidden, js
content shown
For this case, using <div> element is advantageous.
In summary
Use <noscript> element if rendering of the HTML content depends on third-party scripts or if the required script is inline. Else, use <div> element and make sure that the required script contains:
document.getElementById('noscript').style.display='none';
Although Tor Valamo has an elegant answer to this problem, there is an issue which may cause you to opt out of using this technique.
The problem is (usually) IE. It has the tendency to load and execute the JS a bit slower than other browsers causing it to sometimes flash the "Please Enable Your Javascript" div for a split second before it then loads the JS and hides the div.
It is annoying and to get around this you can implement the "classic". <noscript> redirect approach.
<head>
<noscript><meta http-equiv="refresh" content="0; URL=/NO_SCRIPT_URL/ROUTE_HERE"/></noscript>
</head>
This is the most solid technique that I've come across with regards to this little nasty.
One useful application for noscript that I've seen is for a progressively-enhanced async loading of heavy content (especially "below the fold"). Big images, iframes, etc. can be wrapped in noscript in the HTML source, and then the unwrapped elements can be appended to the page using JavaScript after the DOM is ready. This unblocks the page and can make for a much quicker initial loading experience, especially if your interface relies on JS/JQ interactions applied after the document is ready (2 seconds vs. 6 seconds for a portfolio page I consulted on).
These days it seems almost every browser runs Javascript, but you can never know who is going to be accessing your site. These days even screen readers and web crawlers use Javascript, and sometimes make AJAX requests if they have to.
That said, if you're going to fall back to no-Javascript, there is a much better way than a <noscript> tag. Simply do this in the HEAD of your document:
<script type="text/javascript">
document.getElementsByTagName('html')[0].className += ' Q_js'; // better than noscript
</script>
With this technique, you can easily refer to the Q_js class in your CSS to hide things. With the <noscript> tag, the best you can hope for is to include an additional CSS file to override previous CSS. This becomes important when some elements with static content are supposed to be hidden right away (not flicker) until Javascript can make them more dynamic.
In short, the technique I suggested addresses all your cons 1-5, and I believe it's strictly better than using <noscript>.
In the (hopefully near) future you will be able to use css #media scripting:
#media (scripting: none) {
/* styles for when JS is disabled */
}
I create a full height, full width, position:fixed div in all pages with some id .
<div id='noscript_div' style='position:fixed;z-index:20000000;height:100%;width:100%;line-height:100%;'>enable JS buddy</div>
$('#noscript_div').hide();
$(document).ready(function(event){
});
I am not an expert . This worked for me .
I am sorry but, this case will suit only if you want the user to have his javascript enabled always
the simple ideea is in this times your website may adapt to no javascript usage on slow devices using noscript tag like an entity for the entire content of your website**(your html should be prepared to no javascript and all controls must work also if javascript is off,users using basic html controls shoul be able to do everything they done before when javascript was active.So <noscript></noscript> can be the dynamic switch to the same content in other way with the same results=solving the problem wich is the reason the users open your url).**You can see is no matter javascript is or not present ,the website's functionality can be "the same" in any cases js enabled / disabled.On chinese slow devices eg:Samsung neo mini phone this method can run an website without any delays on low internet traffic..
try to run this auto double functionallity website if js is on/off cases:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><HTML>
<HEAD>
<TITLE>noscript can change the Internet forever</TITLE>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
</HEAD>
<BODY>
<SCRIPT LANGUAGE="JavaScript">
<!--
$(document).ready(function(){
$('noscript').replaceWith(function() {
return this.textContent || this.innerText;
});
$("p#javascripton").css("background-color", "yellow");
$("p").click(function(){
$(this).hide();
});
});
//-->
</SCRIPT>
<noscript>
<p>
Noscript's usage today can be logical for <p id="javascripton">eg pc/laptop/high quality tablets usage the complete website with all features:images high resolution,javascript<br><h1>OR without javascript so no high resolutions images inserted with a jquery automated script generated from some php+javascript scripts so have usage for 80% mobile application cause almost are from China ,so low quality products=low cpu,low ram :IN THIS CASE SOMEONE CAN THINK TO SWITCH HIS PHONE TO NO JAVASCRIPT USAGE SO IF ANY PROGRAMMER CAN ADAPT AN ENTIRELY APPLICATION TO THE METHOD I USED IN THIS EXAMPLE AUTOMATED HIS BROWSER IS ADAPT FOR ANY RANDOM ACTION ABOUT THE USER CHOISE(YOU UNDERSTAND "TO USE OR NOT JAVASCRIPT") SO HIS CHINESE PHONE CAN BE APROXIMATELLY APROACH LIKE QUALITY OF SPEED EXECUTION THE OTHERS PC/LAPTOPS/TABLETS QUALITY PRODUCTS.<BR><BR>This stupid example is the best example how no script tag can change the quality of services on this planet ,boost the speed of the internet connection and stops unnecessary use of A LOT OF INTERNET TRAFFIC on slow devices..a simple tag can change the entirely dynamic of programmer's views so entirely Planet's beneficts</h1><p> <br>
run this code in two instances :<br>with browser javascript enable <br>and without(browser's javascript disable or eg a firefox plugin noscript states on/off)
</p>
</noscript>
</BODY></HTML>
and to say more on this .. right noscript was invented to work like a trigger when js is disabled but you can work around this feature to change the course of internet functionality about how is now ,to change it's dynamics....
Like all things, use the right tool for the job.
If you are using Google Maps API, you have a static image via tag and that gets replaced with dynamic JS map. Google have recently started charging for everything thus with the above example it's going to cost you twice, once for static and once for dynamic. The static map is only relevant if JS is disabled. Therefore to save double paying it seems to me the best solution is to wrap the tag for the static map in a tag.